PAT 1040. Longest Symmetric String

#include<iostream>

#include<cstdio>

#include<string>

#include<cstring>

#include<queue>

#include<vector>

#include<cmath>

#include<iomanip>

#include<algorithm>

using namespace std;



//回文有两种情况：aba或者abba，即有对称点和无对称点。

int getSymLen(char *str,int pos)

{

	int len = strlen(str);

	int iCount1 = 0,low,high;



	//处理aba的情况

	low = pos - 1;

	high = pos + 1;

	while(low>=0 && high<len && str[low] == str[high])

	{

		iCount1++;

		low--;

		high++;

	}

	int len1 = 2*iCount1+1;



	//处理abba的情况；

	int iCount2 = 0;

	low = pos;

	high = pos + 1;

	while(low>=0 && high<len && str[low] == str[high])

	{

		iCount2++;

		low--;

		high++;

	}

	int len2 = 2*iCount2;

	return len1>len2?len1:len2;

}



int main()

{

	char str[1005];

	gets(str);

	int maxLen = 1,t,i;

	int len = strlen(str);

	for(i=0; i<len; i++)

	{

		t = getSymLen(str,i);

		if(t > maxLen)

			maxLen = t;

	}

	cout<<maxLen<<endl;

	return 0;

}