1088 最长回文子串

#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std ; 

#define maxn 1000+50

char str[maxn] ; 

int main(){
    while(~scanf(" %s" , str)){
        int max_len = 0 ; 
        int len = strlen(str) ; 
        for(int i=0 ; i<len ; i++){//枚举回文串中心起点
            for(int j=0 ;i+j<len&&i-j>=0 ; j++){//从小到大枚举回文串单向长度
                if(str[i+j] != str[i-j]){//奇数串
                    break ; 
                }
                int count = 2 * j  + 1 ;
                if(max_len < count){
                    max_len = count ; 
                } 
            } 
            for(int j=0 ;i-j>=0&&i+j+1<len ; j++){//偶数串
                if(str[i-j]!=str[i+j+1]){
                    break ; 
                }
                int count = 2 * j + 2 ; 
                if(max_len<count)
                    max_len = count ; 
            }
        } 
        printf("%d\n" , max_len) ; 
    }
    return 0 ; 
}