棧–判斷迴文字串

思路

將字串的前半部分依次壓棧，再依次出棧後和字串後半部分一一比較。

程式碼

#include <stdio.h>
#include <string.h>
#define LEN 8
int main()
{
    char a[LEN] = "abcddcba";
    char s[LEN];
    int i, len, mid, next, top;

    len = LEN;
    mid = len/2;

    if (len%2 == 0) {
        next = mid;
    } else {
        next
 
 = mid + 1;
    }

    top = 0;
    for (i = 0; i < mid; i++) {
        s[++top] = a[i];
    }

    for (i = next; i < len; i++) {
        if (a[i] != s[top]){
            break;
        }
        top--;
    }

    if (top == 0) {
        printf("YES");
    } else {
        printf("NO");
    }

    return 0
 
;
}