06_最长回文子串长度

一、测试程序

/*
 *    最长回文子串长度
 *
 */

#include <stdio.h>
#include <string.h>

#define MAX(a, b)    (a)>(b) ? (a):(b)

int get_lps_len(unsigned char *str)
{
    unsigned int len = 0;
    int right = 0;
    int left = 0;
    int max = 0;
    int i = 0;
    int j = 0;
    
    len =  strlen(str);
    for (; i<len; i++) {
        j = 3;
        while (--j) {
            left = i;
            right = left + j;
            while (left>=0 && right<len && str[left]==str[right]) {                // 分别穷举长度为奇数和偶数的回文子串
                left--;
                right++;
            }
            max = MAX(max, right-left-1);
        }
    }
    
    return max;
}

int main()
{
    unsigned char str[10240] = {0};
    
    while (gets(str))
        printf("%d
", get_lps_len(str));
    
    return 0;
}