数据结构之栈和队列

1.栈

#include <cstdio>
#include <iostream>
using namespace std;
const int stack_size = 10;
const int ex_size = 1;
typedef struct{
    int *base, *top;
    int size;
}stack;
void init(stack &s){
    s.base = s.top = new int[stack_size];
    s.size = stack_size;
}
int length(stack &s){
    return s.top - s.base;
}
void ex_stack(stack &s){
    s.size += ex_size;
    int *p = s.base, *t = new int[s.size];
    int len = length(s); s.base = t;
    for(int i = 0; i < len; ++i) *t++ = p[i];
    s.top = t;
    delete[] p;
}
void destroy(stack &s){
    delete[] s.base;
    s.base = s.top = NULL;
    s.size = -1;
}
void clear(stack &s){
    s.top = s.base;
}
bool empty(stack &s){
    if(s.top == s.base) return true;
    return false;
}
void push(stack &s, int x){
    if(length(s) == s.size) ex_stack(s);
    *s.top++ = x;
}
void pop(stack &s){
    if(empty(s)) return;
    --s.top;
}
int *get(stack &s){
    if(empty(s)) return NULL;
    return s.top-1;
}
void display(stack &s){
    if(empty(s)) cout << "stack is empty!";
    else for(int *p = s.base; p != s.top; ++p) cout << *p << " ";
    cout << endl;
}
int main(){
    stack s; init(s);
    for(int i = 0; i < 10; ++i) push(s,i);
    display(s); push(s,10); display(s);
    pop(s); display(s); cout << *get(s) << endl;
    clear(s); cout << "len = " << length(s) << endl;
    destroy(s); if(s.size == -1 && !s.base && !s.top) cout << "Successful destruction." << endl;
    return 0;
}

2.队列

#include <cstdio>
#include <iostream>
using namespace std;
typedef struct Node{
    int x;
    struct Node *next;
}node;
typedef struct{
    node *front, *rear;
    int length;
}queue;
void init(queue &q){
    node *t = new node;
    t->x = 0;
    t->next = NULL;
    q.front = q.rear = t;
    q.length = 0;
}
void del(queue &q, node *h){
    if(h == NULL) return;
    del(q,h->next);
    delete h;
    h = NULL;
}
void destroy(queue &q){
    del(q,q.front);
    q.front = q.rear = NULL;
    q.length = -1;
}
void clear(queue &q){
    q.rear = q.front;
    q.length = 0;
}
bool empty(queue &q){
    if(q.length) return false;
    return true;
}
int *get(queue &q){
    if(empty(q)) return NULL;
    return &(q.front->x);
}
void push(queue &q, int x){
    q.rear->x = x;
    ++q.length;
    if(q.rear->next == NULL){
        node *t = new node;
        t->x = 0; t->next = NULL;
        q.rear->next = t;
    }
    q.rear = q.rear->next;
}
void pop(queue &q){
    node *p = q.front->next;
    delete q.front;
    q.front = p;
    --q.length;
}
void display(queue &q){
    if(empty(q)) cout << "Queue is empty!";
    else for(node *p = q.front; p != q.rear; p = p->next) cout << p->x << " ";
    cout << endl;
}
int main(){
    queue q; init(q);
    for(int i = 0; i < 10; ++i) push(q,i);
    display(q); cout << *get(q) << endl;
    pop(q); display(q);
    clear(q); cout << q.length << endl;
    destroy(q); if(q.length == -1 && !q.front && !q.rear) cout << "Successful destruction." << endl;
    return 0;
}

 3.循环队列

#include <cstdio>
#include <iostream>
using namespace std;
const int maxn = 10;//仅能装下maxn - 1个元素。
typedef struct{
    int *base;
    int front, rear;
}squeue;
void init(squeue &q, int max_len){
    int *p = new int[max_len];
    if(!p) return;
    q.base = p;
    q.front = q.rear = 0;
}
int length(squeue &q){
    return (q.rear - q.front + maxn) % maxn;
}
bool empty(squeue &q){
    if(q.rear == q.front) return true;
    return false;
}
bool full(squeue &q){
    if((q.rear + 1) % maxn == q.front) return true;
    return false;
}
void push(squeue &q, int x){
    if(full(q)) return;
    q.base[q.rear] = x;
    q.rear = (q.rear + 1) % maxn;
}
void pop(squeue &q){
    if(empty(q)) return;
    q.front = (q.front + 1) % maxn;
}
int get(squeue &q){
    return q.base[q.front];
}
void next(int &i){
    ++i;
    if(i == maxn) i = 0;
}
void display(squeue &q){
    if(empty(q)) return;
    for(int i = q.front; i != q.rear; next(i)) cout << q.base[i] << " ";
    cout << endl;
}
int main(){
    squeue q; init(q,maxn);
    for(int i = 0; i < 9; ++i) push(q,i);
    display(q); pop(q); pop(q); push(q,9);
    display(q);
}