PAT(甲级)1040

1040. Longest Symmetric String (25)

时间限制

400 ms

内存限制

65536 kB

代码长度限制

16000 B

判题程序

Standard

作者

CHEN, Yue

Given a string, you are supposed to output the length of the longest symmetric sub-string. For example, given "Is PAT&TAP symmetric?", the longest symmetric sub-string is "s PAT&TAP s", hence you must output 11.

Input Specification:

Each input file contains one test case which gives a non-empty string of length no more than 1000.

Output Specification:

For each test case, simply print the maximum length in a line.

Sample Input:

Is PAT&TAP symmetric?

Sample Output:

11

#include <stdio.h>
#include <string.h>
#define MAX 1003

char str[MAX];


int main()
{
	gets(str);
	int length = strlen(str);
	int cnt1=0;
	int cnt2=0;
	int i,j;
	int tmp;
	for(i=0;i<length;i++){
		for(j=0;i-j>=0&&j+i<length;j++){
			if(str[i-j] != str[i+j])
			    break;
			else{
				tmp =2*j+1;
				if(cnt1 < tmp)
				    cnt1 = tmp;
			}
		}
		for(j=0;i-j>=0&&i+1+j<length;j++){
			if(str[i-j] != str[i+j+1]) 
			    break;
			else{
				tmp = 2*j+2;
				if(cnt2 <tmp)
				    cnt2 = tmp;
			}
		}
	}
	if(cnt1 <cnt2)
	    cnt1 =cnt2;

	printf("%d\n",cnt1);
	return 0;
}