剑指offer 面试题21 包含min函数的栈

来源：互联网发布：刷空间人气软件编辑：程序博客网时间：2024/05/17 06:51

思路：

建立一个辅助栈，每次push的时候同时push当前的最小值到辅助栈。

#include <stdio.h>#include <stdlib.h>#define STACKSIZE 1024typedef struct Stack{int data[STACKSIZE];int vice[STACKSIZE];int topIndex;}MinStack;MinStack* init(MinStack *s);int min(MinStack *s);int top(MinStack *s);int pop(MinStack *s);MinStack* push(MinStack *s, int data);int main(int argc, char *argv[]){int arr[] = {3,1,5,4,2,8,0,7,9};MinStack *s = NULL;int i, t, m;for(i = 0 ; i<sizeof(arr)/sizeof(int) ; i++){s = push(s, arr[i]);}for(i = 0 ; i<sizeof(arr)/sizeof(int) ; i++){m = min(s);t = pop(s);printf("m = %d\t t = %d\n", m, t);}           printf("\n");return 0;}int min(MinStack *s){if((s == NULL)||(s->topIndex == -1)){printf("MinStack is NULL");return 0;}return s->vice[s->topIndex];}MinStack* init(MinStack *s){if(s == NULL){s = (MinStack*)(malloc(sizeof(MinStack)));}s->topIndex = -1;return s;}int top(MinStack *s){if((s == NULL)||(s->topIndex == -1)){printf("MinStack is NULL");return 0;}return s->data[s->topIndex];}int pop(MinStack *s){if((s == NULL)||(s->topIndex == -1)){printf("MinStack is NULL");return 0;}int d = s->data[s->topIndex];s->topIndex--;//s->topIndex = s->topIndex-1; return d;}MinStack* push(MinStack *s, int data){if(s == NULL){s = init(s);                                                                                                              }if(s->topIndex >= STACKSIZE){     //检查   printf("out of range!\n");  return s;}s->topIndex = s->topIndex+1;s->data[s->topIndex] = data;if(s->topIndex == 0){            //注意首个元素插入时候的特殊情况 s->vice[s->topIndex] = data;return s;}if(data < s->vice[s->topIndex-1]){s->vice[s->topIndex] = data;}else{s->vice[s->topIndex] = s->vice[s->topIndex-1] ;}return s;}

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