剑指Offer第4章 解决面试题的思路

#if 0
void MirrorRecursively(BinaryTreeNode *pNode){
    if(pNode==0||pNode->m_pLeft==0&&pNode->m_pRight==0)
        return ;
    swap(pNode->m_pLeft,pNode->m_pRight);
    if(pNode->m_pLeft)
        MirrorRecursively(pNode->m_pLeft);
    if(pNode->m_pRight)
        MirrorRecursively(pNode->m_pRight);
}
void MirrorIteratively(BinaryTreeNode* pRoot){
    if(pRoot==0||pRoot->m_pLeft==0&&pRoot->m_pRight==0)
        return ;
    stack<BinaryTreeNode*> st;
    st.push(pRoot);
    while(!st.empty()){
        BinaryTreeNode* t=st.top();
        st.pop();
        swap(t->m_pLeft,t->m_pRight);
        if(t->m_pLeft)
            st.push(t->m_pLeft);
        if(t->m_pRight)
            st.push(t->m_pRight);
    }
}
// ====================测试代码====================
// 测试完全二叉树：除了叶子节点，其他节点都有两个子节点
//            8
//        6      10
//       5 7    9  11
void Test1()
{
    printf("=====Test1 starts:=====\n");
    BinaryTreeNode* pNode8 = CreateBinaryTreeNode(8);
    BinaryTreeNode* pNode6 = CreateBinaryTreeNode(6);
    BinaryTreeNode* pNode10 = CreateBinaryTreeNode(10);
    BinaryTreeNode* pNode5 = CreateBinaryTreeNode(5);
    BinaryTreeNode* pNode7 = CreateBinaryTreeNode(7);
    BinaryTreeNode* pNode9 = CreateBinaryTreeNode(9);
    BinaryTreeNode* pNode11 = CreateBinaryTreeNode(11);

    ConnectTreeNodes(pNode8, pNode6, pNode10);
    ConnectTreeNodes(pNode6, pNode5, pNode7);
    ConnectTreeNodes(pNode10, pNode9, pNode11);

    PrintTree(pNode8);

    printf("=====Test1: MirrorRecursively=====\n");
    MirrorRecursively(pNode8);
    PrintTree(pNode8);

    printf("=====Test1: MirrorIteratively=====\n");
    MirrorIteratively(pNode8);
    PrintTree(pNode8);

    DestroyTree(pNode8);
}

// 测试二叉树：出叶子结点之外，左右的结点都有且只有一个左子结点
//            8
//          7   
//        6 
//      5
//    4
void Test2()
{
    printf("=====Test2 starts:=====\n");
    BinaryTreeNode* pNode8 = CreateBinaryTreeNode(8);
    BinaryTreeNode* pNode7 = CreateBinaryTreeNode(7);
    BinaryTreeNode* pNode6 = CreateBinaryTreeNode(6);
    BinaryTreeNode* pNode5 = CreateBinaryTreeNode(5);
    BinaryTreeNode* pNode4 = CreateBinaryTreeNode(4);

    ConnectTreeNodes(pNode8, pNode7, NULL);
    ConnectTreeNodes(pNode7, pNode6, NULL);
    ConnectTreeNodes(pNode6, pNode5, NULL);
    ConnectTreeNodes(pNode5, pNode4, NULL);

    PrintTree(pNode8);

    printf("=====Test2: MirrorRecursively=====\n");
    MirrorRecursively(pNode8);
    PrintTree(pNode8);

    printf("=====Test2: MirrorIteratively=====\n");
    MirrorIteratively(pNode8);
    PrintTree(pNode8);

    DestroyTree(pNode8);
}

// 测试二叉树：出叶子结点之外，左右的结点都有且只有一个右子结点
//            8
//             7   
//              6 
//               5
//                4
void Test3()
{
    printf("=====Test3 starts:=====\n");
    BinaryTreeNode* pNode8 = CreateBinaryTreeNode(8);
    BinaryTreeNode* pNode7 = CreateBinaryTreeNode(7);
    BinaryTreeNode* pNode6 = CreateBinaryTreeNode(6);
    BinaryTreeNode* pNode5 = CreateBinaryTreeNode(5);
    BinaryTreeNode* pNode4 = CreateBinaryTreeNode(4);

    ConnectTreeNodes(pNode8, NULL, pNode7);
    ConnectTreeNodes(pNode7, NULL, pNode6);
    ConnectTreeNodes(pNode6, NULL, pNode5);
    ConnectTreeNodes(pNode5, NULL, pNode4);

    PrintTree(pNode8);

    printf("=====Test3: MirrorRecursively=====\n");
    MirrorRecursively(pNode8);
    PrintTree(pNode8);

    printf("=====Test3: MirrorIteratively=====\n");
    MirrorIteratively(pNode8);
    PrintTree(pNode8);

    DestroyTree(pNode8);
}

// 测试空二叉树：根结点为空指针
void Test4()
{
    printf("=====Test4 starts:=====\n");
    BinaryTreeNode* pNode = NULL;

    PrintTree(pNode);

    printf("=====Test4: MirrorRecursively=====\n");
    MirrorRecursively(pNode);
    PrintTree(pNode);

    printf("=====Test4: MirrorIteratively=====\n");
    MirrorIteratively(pNode);
    PrintTree(pNode);
}

// 测试只有一个结点的二叉树
void Test5()
{
    printf("=====Test5 starts:=====\n");
    BinaryTreeNode* pNode8 = CreateBinaryTreeNode(8);

    PrintTree(pNode8);

    printf("=====Test4: MirrorRecursively=====\n");
    MirrorRecursively(pNode8);
    PrintTree(pNode8);

    printf("=====Test4: MirrorIteratively=====\n");
    MirrorIteratively(pNode8);
    PrintTree(pNode8);
}

int main(int argc, char* argv[])
{
    Test1();
    Test2();
    Test3();
    Test4();
    Test5();

    return 0;
}

#endif

#if 0
void PrintMatrixInCircle(int** numbers, int columns, int rows, int start);
void printNumber(int number);

void PrintMatrixClockwisely(int** numbers, int columns, int rows)
{
    if(numbers == NULL || columns <= 0 || rows <= 0)
        return;

    int start = 0;

    while(columns > start * 2 && rows > start * 2)
    {
        PrintMatrixInCircle(numbers, columns, rows, start);

        ++start;
    }
}

void PrintMatrixInCircle(int** numbers, int columns, int rows, int start)
{
    int endX = columns - 1 - start;
    int endY = rows - 1 - start;

    // 从左到右打印一行
    for(int i = start; i <= endX; ++i)
    {
        int number = numbers[start][i];
        printNumber(number);
    }

    // 从上到下打印一列
    if(start < endY)
    {
        for(int i = start + 1; i <= endY; ++i)
        {
            int number = numbers[i][endX];
            printNumber(number);
        }
    }

    // 从右到左打印一行
    if(start < endX && start < endY)
    {
        for(int i = endX - 1; i >= start; --i)
        {
            int number = numbers[endY][i];
            printNumber(number);
        }
    }

    // 从下到上打印一行
    if(start < endX && start < endY - 1)
    {
        for(int i = endY - 1; i >= start + 1; --i)
        {
            int number = numbers[i][start];
            printNumber(number);
        }
    }
}

void printNumber(int number)
{
    printf("%d\t", number);
}

// ====================测试代码====================
void Test(int columns, int rows)
{
    printf("Test Begin: %d columns, %d rows.\n", columns, rows);

    if(columns < 1 || rows < 1)
        return;

    int** numbers = new int*[rows];
    for(int i = 0; i < rows; ++i)
    {
        numbers[i] = new int[columns];
        for(int j = 0; j < columns; ++j)
        {
            numbers[i][j] = i * columns + j + 1;
        }
    }

    PrintMatrixClockwisely(numbers, columns, rows);
    printf("\n");

    for(int i = 0; i < rows; ++i)
        delete[] (int*)numbers[i];

    delete[] numbers;
}

int main(int argc, char* argv[])
{
    /*
    1    
    */
    Test(1, 1);

    /*
    1    2
    3    4
    */
    Test(2, 2);

    /*
    1    2    3    4
    5    6    7    8
    9    10   11   12
    13   14   15   16
    */
    Test(4, 4);

    /*
    1    2    3    4    5
    6    7    8    9    10
    11   12   13   14   15
    16   17   18   19   20
    21   22   23   24   25
    */
    Test(5, 5);

    /*
    1
    2
    3
    4
    5
    */
    Test(1, 5);

    /*
    1    2
    3    4
    5    6
    7    8
    9    10
    */
    Test(2, 5);

    /*
    1    2    3
    4    5    6
    7    8    9
    10   11   12
    13   14   15
    */
    Test(3, 5);

    /*
    1    2    3    4
    5    6    7    8
    9    10   11   12
    13   14   15   16
    17   18   19   20
    */
    Test(4, 5);

    /*
    1    2    3    4    5
    */
    Test(5, 1);

    /*
    1    2    3    4    5
    6    7    8    9    10
    */
    Test(5, 2);

    /*
    1    2    3    4    5
    6    7    8    9    10
    11   12   13   14    15
    */
    Test(5, 3);

    /*
    1    2    3    4    5
    6    7    8    9    10
    11   12   13   14   15
    16   17   18   19   20
    */
    Test(5, 4);

    return 0;
}

#endif

#if 0
template <typename T> class StackWithMin
{
public:
    StackWithMin(void) {}
    virtual ~StackWithMin(void) {}

    T& top(void);
    const T& top(void) const;

    void push(const T& value);
    void pop(void);

    const T& min(void) const;

    bool empty() const;
    size_t size() const;

private:
    std::stack<T>   m_data;     // 数据栈，存放栈的所有元素
    std::stack<T>   m_min;      // 辅助栈，存放栈的最小元素
};

template <typename T> void StackWithMin<T>::push(const T& value)
{
    // 把新元素添加到辅助栈
    m_data.push(value);

    // 当新元素比之前的最小元素小时，把新元素插入辅助栈里；
    // 否则把之前的最小元素重复插入辅助栈里
    if(m_min.size() == 0 || value < m_min.top())
        m_min.push(value);
    else
        m_min.push(m_min.top());
}

template <typename T> void StackWithMin<T>::pop()
{
    assert(m_data.size() > 0 && m_min.size() > 0);

    m_data.pop();
    m_min.pop();
}


template <typename T> const T& StackWithMin<T>::min() const
{
    assert(m_data.size() > 0 && m_min.size() > 0);

    return m_min.top();
}

template <typename T> T& StackWithMin<T>::top()
{
    return m_data.top();
}

template <typename T> const T& StackWithMin<T>::top() const
{
    return m_data.top();
}

template <typename T> bool StackWithMin<T>::empty() const
{
    return m_data.empty();
}

template <typename T> size_t StackWithMin<T>::size() const
{
    return m_data.size();
}
void Test(char* testName, const StackWithMin<int>& stack, int expected)
{
    if(testName != NULL)
        printf("%s begins: ", testName);

    if(stack.min() == expected)
        printf("Passed.\n");
    else
        printf("Failed.\n");
}

int main(int argc, char* argv[])
{
    StackWithMin<int> stack;

    stack.push(3);
    Test("Test1", stack, 3);

    stack.push(4);
    Test("Test2", stack, 3);

    stack.push(2);
    Test("Test3", stack, 2);

    stack.push(3);
    Test("Test4", stack, 2);

    stack.pop();
    Test("Test5", stack, 2);

    stack.pop();
    Test("Test6", stack, 3);

    stack.pop();
    Test("Test7", stack, 3);

    stack.push(0);
    Test("Test8", stack, 0);

    return 0;
}


#endif

#if 0
bool IsPopOrder(const int* pPush, const int* pPop, int nLength){
    if(pPush==0||pPop==0||nLength<=0)
        return false;
    const int *p=pPush;
    const int *q=pPop;
    stack<int> st;
    while(q-pPop<nLength){
        while(st.empty()||st.top()!=*q){
            if(p-pPush==nLength)
                break;
            st.push(*p);
            p++;
        }
        if(st.top()!=*q&&p-pPush==nLength)
            return false;
        st.pop();
        q++;
    }
    return st.empty()&&q-pPop==nLength;
}
// ====================测试代码====================
void Test(char* testName, const int* pPush, const int* pPop, int nLength, bool expected)
{
    if(testName != NULL)
        printf("%s begins: ", testName);

    if(IsPopOrder(pPush, pPop, nLength) == expected)
        printf("Passed.\n");
    else
        printf("failed.\n");
}

void Test1()
{
    const int nLength = 5;
    int push[nLength] = {1, 2, 3, 4, 5};
    int pop[nLength] = {4, 5, 3, 2, 1};
    
    Test("Test1", push, pop, nLength, true);
}

void Test2()
{
    const int nLength = 5;
    int push[nLength] = {1, 2, 3, 4, 5};
    int pop[nLength] = {3, 5, 4, 2, 1};
    
    Test("Test2", push, pop, nLength, true);
}

void Test3()
{
    const int nLength = 5;
    int push[nLength] = {1, 2, 3, 4, 5};
    int pop[nLength] = {4, 3, 5, 1, 2};
    
    Test("Test3", push, pop, nLength, false);
}

void Test4()
{
    const int nLength = 5;
    int push[nLength] = {1, 2, 3, 4, 5};
    int pop[nLength] = {3, 5, 4, 1, 2};
    
    Test("Test4", push, pop, nLength, false);
}

// push和pop序列只有一个数字
void Test5()
{
    const int nLength = 1;
    int push[nLength] = {1};
    int pop[nLength] = {2};

    Test("Test5", push, pop, nLength, false);
}

void Test6()
{
    const int nLength = 1;
    int push[nLength] = {1};
    int pop[nLength] = {1};

    Test("Test6", push, pop, nLength, true);
}

void Test7()
{
    Test("Test7", NULL, NULL, 0, false);
}
 
int main(int argc, char* argv[])
{
    Test1();
    Test2();
    Test3();
    Test4();
    Test5();
    Test6();
    Test7();

    return 0;
}


#endif

#if 0
void PrintFromTopToBottom(BinaryTreeNode* pRoot)
{
    if(pRoot == NULL)
        return;

    std::deque<BinaryTreeNode *> dequeTreeNode;

    dequeTreeNode.push_back(pRoot);

    while(dequeTreeNode.size())
    {
        BinaryTreeNode *pNode = dequeTreeNode.front();
        dequeTreeNode.pop_front();

        printf("%d ", pNode->m_nValue);

        if(pNode->m_pLeft)
            dequeTreeNode.push_back(pNode->m_pLeft);

        if(pNode->m_pRight)
            dequeTreeNode.push_back(pNode->m_pRight);
    }
}

// ====================测试代码====================
void Test(char* testName, BinaryTreeNode* pRoot)
{
    if(testName != NULL)
        printf("%s begins: \n", testName);

    PrintTree(pRoot);

    printf("The nodes from top to bottom, from left to right are: \n");
    PrintFromTopToBottom(pRoot);

    printf("\n\n");
}

//            10
//         /      \
//        6        14
//       /\        /\
//      4  8     12  16
void Test1()
{
    BinaryTreeNode* pNode10 = CreateBinaryTreeNode(10);
    BinaryTreeNode* pNode6 = CreateBinaryTreeNode(6);
    BinaryTreeNode* pNode14 = CreateBinaryTreeNode(14);
    BinaryTreeNode* pNode4 = CreateBinaryTreeNode(4);
    BinaryTreeNode* pNode8 = CreateBinaryTreeNode(8);
    BinaryTreeNode* pNode12 = CreateBinaryTreeNode(12);
    BinaryTreeNode* pNode16 = CreateBinaryTreeNode(16);

    ConnectTreeNodes(pNode10, pNode6, pNode14);
    ConnectTreeNodes(pNode6, pNode4, pNode8);
    ConnectTreeNodes(pNode14, pNode12, pNode16);

    Test("Test1", pNode10);

    DestroyTree(pNode10);
}

//               5
//              /
//             4
//            /
//           3
//          /
//         2
//        /
//       1
void Test2()
{
    BinaryTreeNode* pNode5 = CreateBinaryTreeNode(5);
    BinaryTreeNode* pNode4 = CreateBinaryTreeNode(4);
    BinaryTreeNode* pNode3 = CreateBinaryTreeNode(3);
    BinaryTreeNode* pNode2 = CreateBinaryTreeNode(2);
    BinaryTreeNode* pNode1 = CreateBinaryTreeNode(1);

    ConnectTreeNodes(pNode5, pNode4, NULL);
    ConnectTreeNodes(pNode4, pNode3, NULL);
    ConnectTreeNodes(pNode3, pNode2, NULL);
    ConnectTreeNodes(pNode2, pNode1, NULL);

    Test("Test2", pNode5);

    DestroyTree(pNode5);
}

// 1
//  \
//   2
//    \
//     3
//      \
//       4
//        \
//         5
void Test3()
{
    BinaryTreeNode* pNode1 = CreateBinaryTreeNode(1);
    BinaryTreeNode* pNode2 = CreateBinaryTreeNode(2);
    BinaryTreeNode* pNode3 = CreateBinaryTreeNode(3);
    BinaryTreeNode* pNode4 = CreateBinaryTreeNode(4);
    BinaryTreeNode* pNode5 = CreateBinaryTreeNode(5);

    ConnectTreeNodes(pNode1, NULL, pNode2);
    ConnectTreeNodes(pNode2, NULL, pNode3);
    ConnectTreeNodes(pNode3, NULL, pNode4);
    ConnectTreeNodes(pNode4, NULL, pNode5);

    Test("Test3", pNode1);

    DestroyTree(pNode1);
}

// 树中只有1个结点
void Test4()
{
    BinaryTreeNode* pNode1 = CreateBinaryTreeNode(1);
    Test("Test4", pNode1);

    DestroyTree(pNode1);
}

// 树中没有结点
void Test5()
{
    Test("Test5", NULL);
}

int main(int argc, char* argv[])
{
    Test1();
    Test2();
    Test3();
    Test4();
    Test5();

   return 0;
}


#endif

#if 0
// BST：Binary Search Tree，二叉搜索树
bool VerifySquenceOfBST(int sequence[], int length){
    if(sequence==0||length<=0)
        return false;
    int r=sequence[length-1];
    int i;
    for(i=0;i<length-1;i++)
        if(sequence[i]>r)
            break;
    for(int j=i;j<length-1;j++)
        if(sequence[j]<r)
            return false;
    bool left=true;
    if(i>0)
        left=VerifySquenceOfBST(sequence,i);
    bool right=true;
    if(i<length-1)
        right=VerifySquenceOfBST(sequence+i,length-1-i);
    return left*right;
}
// ====================测试代码====================
void Test(char* testName, int sequence[], int length, bool expected)
{
    if(testName != NULL)
        printf("%s begins: ", testName);

    if(VerifySquenceOfBST(sequence, length) == expected)
        printf("passed.\n");
    else
        printf("failed.\n");
}

//            10
//         /      \
//        6        14
//       /\        /\
//      4  8     12  16
void Test1()
{
    int data[] = {4, 8, 6, 12, 16, 14, 10};
    Test("Test1", data, sizeof(data)/sizeof(int), true);
}

//           5
//          / \
//         4   7
//            /
//           6
void Test2()
{
    int data[] = {4, 6, 7, 5};
    Test("Test2", data, sizeof(data)/sizeof(int), true);
}

//               5
//              /
//             4
//            /
//           3
//          /
//         2
//        /
//       1
void Test3()
{
    int data[] = {1, 2, 3, 4, 5};
    Test("Test3", data, sizeof(data)/sizeof(int), true);
}

// 1
//  \
//   2
//    \
//     3
//      \
//       4
//        \
//         5
void Test4()
{
    int data[] = {5, 4, 3, 2, 1};
    Test("Test4", data, sizeof(data)/sizeof(int), true);
}

// 树中只有1个结点
void Test5()
{
    int data[] = {5};
    Test("Test5", data, sizeof(data)/sizeof(int), true);
}

void Test6()
{
    int data[] = {7, 4, 6, 5};
    Test("Test6", data, sizeof(data)/sizeof(int), false);
}

void Test7()
{
    int data[] = {4, 6, 12, 8, 16, 14, 10};
    Test("Test7", data, sizeof(data)/sizeof(int), false);
}

void Test8()
{
    Test("Test8", NULL, 0, false);
}

int main(int argc, char* argv[])
{
    Test1();
    Test2();
    Test3();
    Test4();
    Test5();
    Test6();
    Test7();
    Test8();

    return 0;
}


#endif

#if 0
void FindPath(BinaryTreeNode* pRoot, int expectedSum, std::vector<int>& path, int& currentSum);

void FindPath(BinaryTreeNode* pRoot, int expectedSum){
    if(pRoot==0)
        return ;
    vector<int> vec;
    int currentSum=0;
    FindPath(pRoot,expectedSum,vec,currentSum);
}
void FindPath(BinaryTreeNode* pRoot, int expectedSum, std::vector<int>& path, int& currentSum){
    currentSum+=pRoot->m_nValue;
    path.push_back(pRoot->m_nValue);

    bool leaf=pRoot->m_pLeft==0&&pRoot->m_pRight==0;
    if(currentSum==expectedSum&&leaf){
        printf("A path is found: ");
        std::vector<int>::iterator iter = path.begin();
        for(; iter != path.end(); ++ iter)
            printf("%d\t", *iter);
        printf("\n");
    }
    if(pRoot->m_pLeft!=0)
        FindPath(pRoot->m_pLeft,expectedSum,path,currentSum);
    if(pRoot->m_pRight!=0)
        FindPath(pRoot->m_pRight,expectedSum,path,currentSum);
    currentSum-=pRoot->m_nValue;
    path.pop_back();
}

// ====================测试代码====================
void Test(char* testName, BinaryTreeNode* pRoot, int expectedSum)
{
    if(testName != NULL)
        printf("%s begins:\n", testName);

    FindPath(pRoot, expectedSum);

    printf("\n");
}

//            10
//         /      \
//        5        12
//       /\        
//      4  7     
// 有两条路径上的结点和为22
void Test1()
{
    BinaryTreeNode* pNode10 = CreateBinaryTreeNode(10);
    BinaryTreeNode* pNode5 = CreateBinaryTreeNode(5);
    BinaryTreeNode* pNode12 = CreateBinaryTreeNode(12);
    BinaryTreeNode* pNode4 = CreateBinaryTreeNode(4);
    BinaryTreeNode* pNode7 = CreateBinaryTreeNode(7);

    ConnectTreeNodes(pNode10, pNode5, pNode12);
    ConnectTreeNodes(pNode5, pNode4, pNode7);

    printf("Two paths should be found in Test1.\n");
    Test("Test1", pNode10, 22);

    DestroyTree(pNode10);
}

//            10
//         /      \
//        5        12
//       /\        
//      4  7     
// 没有路径上的结点和为15
void Test2()
{
    BinaryTreeNode* pNode10 = CreateBinaryTreeNode(10);
    BinaryTreeNode* pNode5 = CreateBinaryTreeNode(5);
    BinaryTreeNode* pNode12 = CreateBinaryTreeNode(12);
    BinaryTreeNode* pNode4 = CreateBinaryTreeNode(4);
    BinaryTreeNode* pNode7 = CreateBinaryTreeNode(7);

    ConnectTreeNodes(pNode10, pNode5, pNode12);
    ConnectTreeNodes(pNode5, pNode4, pNode7);

    printf("No paths should be found in Test2.\n");
    Test("Test2", pNode10, 15);

    DestroyTree(pNode10);
}

//               5
//              /
//             4
//            /
//           3
//          /
//         2
//        /
//       1
// 有一条路径上面的结点和为15
void Test3()
{
    BinaryTreeNode* pNode5 = CreateBinaryTreeNode(5);
    BinaryTreeNode* pNode4 = CreateBinaryTreeNode(4);
    BinaryTreeNode* pNode3 = CreateBinaryTreeNode(3);
    BinaryTreeNode* pNode2 = CreateBinaryTreeNode(2);
    BinaryTreeNode* pNode1 = CreateBinaryTreeNode(1);

    ConnectTreeNodes(pNode5, pNode4, NULL);
    ConnectTreeNodes(pNode4, pNode3, NULL);
    ConnectTreeNodes(pNode3, pNode2, NULL);
    ConnectTreeNodes(pNode2, pNode1, NULL);

    printf("One path should be found in Test3.\n");
    Test("Test3", pNode5, 15);

    DestroyTree(pNode5);
}

// 1
//  \
//   2
//    \
//     3
//      \
//       4
//        \
//         5
// 没有路径上面的结点和为16
void Test4()
{
    BinaryTreeNode* pNode1 = CreateBinaryTreeNode(1);
    BinaryTreeNode* pNode2 = CreateBinaryTreeNode(2);
    BinaryTreeNode* pNode3 = CreateBinaryTreeNode(3);
    BinaryTreeNode* pNode4 = CreateBinaryTreeNode(4);
    BinaryTreeNode* pNode5 = CreateBinaryTreeNode(5);

    ConnectTreeNodes(pNode1, NULL, pNode2);
    ConnectTreeNodes(pNode2, NULL, pNode3);
    ConnectTreeNodes(pNode3, NULL, pNode4);
    ConnectTreeNodes(pNode4, NULL, pNode5);

    printf("No paths should be found in Test4.\n");
    Test("Test4", pNode1, 16);

    DestroyTree(pNode1);
}

// 树中只有1个结点
void Test5()
{
    BinaryTreeNode* pNode1 = CreateBinaryTreeNode(1);

    printf("One path should be found in Test5.\n");
    Test("Test5", pNode1, 1);

    DestroyTree(pNode1);
}

// 树中没有结点
void Test6()
{
    printf("No paths should be found in Test6.\n");
    Test("Test6", NULL, 0);
}

int main(int argc, char* argv[])
{
    Test1();
    Test2();
    Test3();
    Test4();
    Test5();
    Test6();

    return 0;
}

#endif

两种方法的代码如下:

#if 0
struct ComplexListNode
{
    int                 m_nValue;
    ComplexListNode*    m_pNext;
    ComplexListNode*    m_pSibling;
};
ComplexListNode* CreateNode(int nValue)
{
    ComplexListNode* pNode = new ComplexListNode();
    
    pNode->m_nValue = nValue;
    pNode->m_pNext = NULL;
    pNode->m_pSibling = NULL;

    return pNode;
}

void BuildNodes(ComplexListNode* pNode, ComplexListNode* pNext, ComplexListNode* pSibling)
{
    if(pNode != NULL)
    {
        pNode->m_pNext = pNext;
        pNode->m_pSibling = pSibling;
    }
}

void PrintList(ComplexListNode* pHead)
{
    ComplexListNode* pNode = pHead;
    while(pNode != NULL)
    {
        printf("The value of this node is: %d.\n", pNode->m_nValue);

        if(pNode->m_pSibling != NULL)
            printf("The value of its sibling is: %d.\n", pNode->m_pSibling->m_nValue);
        else
            printf("This node does not have a sibling.\n");

        printf("\n");

        pNode = pNode->m_pNext;
    }
}

void CloneNodes(ComplexListNode* pHead);
void ConnectSiblingNodes(ComplexListNode* pHead);
ComplexListNode* ReconnectNodes(ComplexListNode* pHead);

ComplexListNode* Clone_(ComplexListNode* pHead){
    if(pHead==0)
        return 0;
    map<ComplexListNode*,ComplexListNode*> mp;
    ComplexListNode* qHead;
    ComplexListNode* p=pHead,**q=&qHead;
    while(p!=0){
        *q=CreateNode(p->m_nValue);
        mp[p]=*q;
        p=p->m_pNext;
        q=&((*q)->m_pNext);
    }
    *q=0;
    p=pHead, q=&qHead;
    while(p!=0){
        (*q)->m_pSibling=mp[p->m_pSibling];
        p=p->m_pNext;
        q=&((*q)->m_pNext);
    }
    return qHead;
}
ComplexListNode* Clone(ComplexListNode* pHead){
    if(pHead==0)
        return 0;
    ComplexListNode* qHead,*p=pHead,*q;
    while(p!=0){
        q=CreateNode(p->m_nValue);
        q->m_pNext=p->m_pNext;
        p->m_pNext=q;
        p=q->m_pNext;
    }
    p=pHead;
    while(p!=0){
        q=p->m_pNext;
        if(p->m_pSibling!=0)
            q->m_pSibling=p->m_pSibling->m_pNext;
        p=q->m_pNext;
    }
    p=pHead;
    ComplexListNode**qq=&qHead;
    while(p->m_pNext!=0){
        *qq=p->m_pNext;
        p->m_pNext=(*qq)->m_pNext;
        qq=&((*qq)->m_pNext);
    }
    *qq=0;
    return qHead;
}
// ====================测试代码====================
void Test(char* testName, ComplexListNode* pHead)
{
    if(testName != NULL)
        printf("%s begins:\n", testName);

    printf("The original list is:\n");
    PrintList(pHead);

    ComplexListNode* pClonedHead = Clone(pHead);

    printf("The cloned list is:\n");
    PrintList(pClonedHead);
}

//          -----------------
//         \|/              |
//  1-------2-------3-------4-------5
//  |       |      /|\             /|\
//  --------+--------               |
//          -------------------------
void Test1()
{
    ComplexListNode* pNode1 = CreateNode(1);
    ComplexListNode* pNode2 = CreateNode(2);
    ComplexListNode* pNode3 = CreateNode(3);
    ComplexListNode* pNode4 = CreateNode(4);
    ComplexListNode* pNode5 = CreateNode(5);

    BuildNodes(pNode1, pNode2, pNode3);
    BuildNodes(pNode2, pNode3, pNode5);
    BuildNodes(pNode3, pNode4, NULL);
    BuildNodes(pNode4, pNode5, pNode2);

    Test("Test1", pNode1);
}

// m_pSibling指向结点自身
//          -----------------
//         \|/              |
//  1-------2-------3-------4-------5
//         |       | /|\           /|\
//         |       | --             |
//         |------------------------|
void Test2()
{
    ComplexListNode* pNode1 = CreateNode(1);
    ComplexListNode* pNode2 = CreateNode(2);
    ComplexListNode* pNode3 = CreateNode(3);
    ComplexListNode* pNode4 = CreateNode(4);
    ComplexListNode* pNode5 = CreateNode(5);

    BuildNodes(pNode1, pNode2, NULL);
    BuildNodes(pNode2, pNode3, pNode5);
    BuildNodes(pNode3, pNode4, pNode3);
    BuildNodes(pNode4, pNode5, pNode2);

    Test("Test2", pNode1);
}

// m_pSibling形成环
//          -----------------
//         \|/              |
//  1-------2-------3-------4-------5
//          |              /|\
//          |               |
//          |---------------|
void Test3()
{
    ComplexListNode* pNode1 = CreateNode(1);
    ComplexListNode* pNode2 = CreateNode(2);
    ComplexListNode* pNode3 = CreateNode(3);
    ComplexListNode* pNode4 = CreateNode(4);
    ComplexListNode* pNode5 = CreateNode(5);

    BuildNodes(pNode1, pNode2, NULL);
    BuildNodes(pNode2, pNode3, pNode4);
    BuildNodes(pNode3, pNode4, NULL);
    BuildNodes(pNode4, pNode5, pNode2);

    Test("Test3", pNode1);
}

// 只有一个结点
void Test4()
{
    ComplexListNode* pNode1 = CreateNode(1);
    BuildNodes(pNode1, NULL, pNode1);

    Test("Test4", pNode1);
}

// 鲁棒性测试
void Test5()
{
    Test("Test5", NULL);
}

int main(int argc, char* argv[])
{
    Test1();
    Test2();
    Test3();
    Test4();
    Test5();

    return 0;
}


#endif

代码如下:

#if 0
void ConvertNode(BinaryTreeNode* pNode, BinaryTreeNode** pLastNodeInList);

BinaryTreeNode* Convert(BinaryTreeNode* pRootOfTree) {
    if(pRootOfTree==0)
        return 0;
    BinaryTreeNode* pLastNodeInList=0;
    ConvertNode(pRootOfTree,&pLastNodeInList);
    while(pLastNodeInList!=0&&pLastNodeInList->m_pLeft!=0){
        pLastNodeInList=pLastNodeInList->m_pLeft;
    }
    return pLastNodeInList;
}
void ConvertNode(BinaryTreeNode* pNode, BinaryTreeNode** pLastNodeInList){
    if(pNode==0)
        return ;
    if(pNode->m_pLeft!=0)
        ConvertNode(pNode->m_pLeft,pLastNodeInList);
    pNode->m_pLeft=*pLastNodeInList;
    if(*pLastNodeInList!=0)
        (*pLastNodeInList)->m_pRight=pNode;
    *pLastNodeInList=pNode;
    if(pNode->m_pRight!=0)
        ConvertNode(pNode->m_pRight,pLastNodeInList);
}
// ====================测试代码====================
void PrintDoubleLinkedList(BinaryTreeNode* pHeadOfList)
{
    BinaryTreeNode* pNode = pHeadOfList;

    printf("The nodes from left to right are:\n");
    while(pNode != NULL)
    {
        printf("%d\t", pNode->m_nValue);

        if(pNode->m_pRight == NULL)
            break;
        pNode = pNode->m_pRight;
    }

    printf("\nThe nodes from right to left are:\n");
    while(pNode != NULL)
    {
        printf("%d\t", pNode->m_nValue);

        if(pNode->m_pLeft == NULL)
            break;
        pNode = pNode->m_pLeft;
    }

    printf("\n");
}

void DestroyList(BinaryTreeNode* pHeadOfList)
{
    BinaryTreeNode* pNode = pHeadOfList;
    while(pNode != NULL)
    {
        BinaryTreeNode* pNext = pNode->m_pRight;

        delete pNode;
        pNode = pNext;
    }
}

void Test(char* testName, BinaryTreeNode* pRootOfTree)
{
    if(testName != NULL)
        printf("%s begins:\n", testName);

    PrintTree(pRootOfTree);

    BinaryTreeNode* pHeadOfList = Convert(pRootOfTree);

    PrintDoubleLinkedList(pHeadOfList);
}

//            10
//         /      \
//        6        14
//       /\        /\
//      4  8     12  16
void Test1()
{
    BinaryTreeNode* pNode10 = CreateBinaryTreeNode(10);
    BinaryTreeNode* pNode6 = CreateBinaryTreeNode(6);
    BinaryTreeNode* pNode14 = CreateBinaryTreeNode(14);
    BinaryTreeNode* pNode4 = CreateBinaryTreeNode(4);
    BinaryTreeNode* pNode8 = CreateBinaryTreeNode(8);
    BinaryTreeNode* pNode12 = CreateBinaryTreeNode(12);
    BinaryTreeNode* pNode16 = CreateBinaryTreeNode(16);

    ConnectTreeNodes(pNode10, pNode6, pNode14);
    ConnectTreeNodes(pNode6, pNode4, pNode8);
    ConnectTreeNodes(pNode14, pNode12, pNode16);

    Test("Test1", pNode10);

    DestroyList(pNode4);
}

//               5
//              /
//             4
//            /
//           3
//          /
//         2
//        /
//       1
void Test2()
{
    BinaryTreeNode* pNode5 = CreateBinaryTreeNode(5);
    BinaryTreeNode* pNode4 = CreateBinaryTreeNode(4);
    BinaryTreeNode* pNode3 = CreateBinaryTreeNode(3);
    BinaryTreeNode* pNode2 = CreateBinaryTreeNode(2);
    BinaryTreeNode* pNode1 = CreateBinaryTreeNode(1);

    ConnectTreeNodes(pNode5, pNode4, NULL);
    ConnectTreeNodes(pNode4, pNode3, NULL);
    ConnectTreeNodes(pNode3, pNode2, NULL);
    ConnectTreeNodes(pNode2, pNode1, NULL);

    Test("Test2", pNode5);

    DestroyList(pNode1);
}

// 1
//  \
//   2
//    \
//     3
//      \
//       4
//        \
//         5
void Test3()
{
    BinaryTreeNode* pNode1 = CreateBinaryTreeNode(1);
    BinaryTreeNode* pNode2 = CreateBinaryTreeNode(2);
    BinaryTreeNode* pNode3 = CreateBinaryTreeNode(3);
    BinaryTreeNode* pNode4 = CreateBinaryTreeNode(4);
    BinaryTreeNode* pNode5 = CreateBinaryTreeNode(5);

    ConnectTreeNodes(pNode1, NULL, pNode2);
    ConnectTreeNodes(pNode2, NULL, pNode3);
    ConnectTreeNodes(pNode3, NULL, pNode4);
    ConnectTreeNodes(pNode4, NULL, pNode5);

    Test("Test3", pNode1);

    DestroyList(pNode1);
}

// 树中只有1个结点
void Test4()
{
    BinaryTreeNode* pNode1 = CreateBinaryTreeNode(1);
    Test("Test4", pNode1);

    DestroyList(pNode1);
}

// 树中没有结点
void Test5()
{
    Test("Test5", NULL);
}

int main(int argc, char* argv[])
{
    Test1();
    Test2();
    Test3();
    Test4();
    Test5();

    return 0;
}


#endif

代码如下:

#if 0
void Permutation(char* pStr, char* pBegin);

void Permutation(char* pStr)
{
    if(pStr == NULL)
        return;

    Permutation(pStr, pStr);
}

void Permutation(char* pStr, char* pBegin)
{
    if(*pBegin == '\0')
    {
        printf("%s\n", pStr);
    }
    else
    {
        for(char* pCh = pBegin; *pCh != '\0'; ++ pCh)
        {
            swap(*pCh,*pBegin);

            Permutation(pStr, pBegin + 1);

            swap(*pCh,*pBegin);
        }
    }
}

// ====================测试代码====================
void Test(char* pStr)
{
    if(pStr == NULL)
        printf("Test for NULL begins:\n");
    else
        printf("Test for %s begins:\n", pStr);

    Permutation(pStr);

    printf("\n");
}

int main(int argc, char* argv[])
{
    Test(NULL);

    char string1[] = "";
    Test(string1);

    char string2[] = "a";
    Test(string2);

    char string3[] = "ab";
    Test(string3);

    char string4[] = "abc";
    Test(string4);

    return 0;
}


#endif