C语言求解数独

平时喜欢玩数独游戏，昨日突发想用程序自动求解。思路是回溯法，不断试探。

程序代码如下：

#include<stdio.h>

/*
{0,0,4,6,0,2,0,9,1},
{2,1,0,9,8,4,0,5,6},
{9,0,0,0,7,1,4,2,0},
{1,2,5,0,6,0,3,4,7},
{4,7,6,0,0,0,9,8,5},
{8,3,9,0,4,0,1,6,2},
{0,9,1,2,5,0,0,0,4},
{5,8,0,4,1,6,0,3,9},
{6,4,0,3,0,7,5,0,0}};
*/

int data[9][9] = {
{0,7,0,2,6,0,9,0,0},
{3,0,0,0,0,8,0,0,7}, 
{0,9,0,0,5,7,0,0,0}, 
{5,0,0,0,0,0,0,7,0}, 
{0,4,7,3,1,2,8,5,0}, 
{0,8,0,0,0,0,0,0,1}, 
{0,0,0,8,2,0,0,4,0}, 
{7,0,0,6,0,0,0,0,2}, 
{0,0,4,0,3,9,0,8,0}};

void input()
{
    int i,j;
    for(i = 0;i < 9;i++)
        for(j = 0;j < 9;j++)
            scanf("%d",&data[i][j]);
}

void output()
{
    int i,j;
    for(i = 0;i < 9;i++)
    {
        for(j = 0;j < 9;j++)
            printf("%d ",data[i][j]);
        printf("\n");
    }
    printf("\n");
}

/*检查num是否可放置在3*3区域是否有冲突*/
int CheckSquare(int line,int col,int num)
{
    int i = (line / 3) * 3;
    int j = (col / 3) * 3;
    int m,n;
    for(m = i;m < i + 3;m++)
        for(n = j;n < j + 3;n++)
            if((data[m][n] == num) && !(m == line && n == col))
                return 0;
    return 1;
}

/*检查行冲突*/
int CheckLine(int line,int col,int num)
{
    int i = 9;
    while(i--)
        if((data[line][i] == num) && (i != col))
            return 0;
    return 1;
}

/*检查列冲突*/
int CheckColumn(int line,int col,int num)
{
    int i = 9;
    while(i--)
        if((data[i][col] == num) && (i != line))
            return 0;
    return 1;
}

/*检查i行j列是否可放置num*/
int Check(int i,int j,int num)
{
    return CheckSquare(i,j,num) && CheckLine(i,j,num) && CheckColumn(i,j,num);
}

/*检查是否完成*/
int IsDone()
{
    int i,j;
    for(i = 0;i < 9;i++)
        for(j = 0;j < 9;j++)
            if(!Check(i,j,data[i][j]) || (data[i][j] == 0))
                return 0;
    return 1;
}

void Calc()
{
    int i,j,x;
    if(IsDone())
    {
        output();
        return;
    }
    for(i = 0;i < 9;i++)
    {
        for(j = 0;j < 9;j++)
        {
            if(data[i][j] == 0)
            {
                for(x = 1; x <= 9;x++)
                {
                    if(Check(i,j,x))
                    {
                        data[i][j] = x;
                        Calc();
                    }
                }
                if(x == 10)
                {
                    data[i][j] = 0;
                    return ;
                }
            }
        }
    }
}

int main()
{
//    input();
    Calc();
    output();

    return 0;
}

上述程序中，数字0表示该位置为空，待填入数字。