最长回文字符串

在一个字符串中，找出最长的回文字符串

// MaxSameReverse.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"
#include<deque>
#include<iostream>
using namespace std;


bool IsReverseTheSame(deque<char>in);
deque<char> substring(deque<char> input,int beg,int end);
bool MaxSameReverse(deque<char>input);

int _tmain(int argc, _TCHAR* argv[])
{
	deque<char>cc;
	cc.push_back('g');
	cc.push_back('a');
	cc.push_back('b');
	cc.push_back('c');
	cc.push_back('b');
	cc.push_back('a');
	if (IsReverseTheSame(cc))//测试IsReverseTheSame函数
		cout << 1 << endl;
	else
		cout << 0 << endl;
	cc.push_back('c');
	cout << cc[2] << endl;

	MaxSameReverse(cc);
	
	system("pause");
	return 0;
}

bool IsReverseTheSame(deque<char>in)
{
	while (in.size() > 2)
	{
		if (in.front() != in.back())
		{
			return false;
		}
		in.pop_back();
		in.pop_front();
		IsReverseTheSame(in);
	}
	if (in.size() == 2)
	{
		if (in[0] == in[1])
			return true;
		return false;
	}
	if (in.size() == 1)
		return true;
}

deque<char> substring(deque<char> input, int beg, int end)
{
	deque<char>out;
	for (int i = beg; i < end + 1; i++)
		out.push_back(input[i]);
	return out;
}


bool MaxSameReverse(deque<char>input)
{
	bool flag = false;
	for (int i = input.size(); i >0; i--)
	{
		for (int k = 0; k < input.size() - i+1; k++)
		{
			deque<char>ww(substring(input, k, i+k - 1));
			
			if (IsReverseTheSame(ww))
			{
				flag = true;
				for (int m = 0; m < ww.size(); m++)
					cout << ww[m];
				cout << endl;
			}
			if (flag)
				break;
		}
		if (flag)
			break;
	}
	return flag;
}

//开始用char*做递归，陷入死循环，后来改用deque

/*
bool IsReverseTheSame(char* in)
{
	while (strlen(in)> 2)
	{
		if (in[0] != in[strlen(in) - 1])
		{
			return false;
		}
		char*out = new char[strlen(in) - 2];
		out = substring(in);
		
		cout << out << endl;
		int pp = strlen(out);
		cout << pp<<endl;
		IsReverseTheSame(out);
		
	}
	if (strlen(in) == 2)
	{
		if (in[0] == in[1])
			return true;
		return false;
	}
	if (strlen(in) == 1)
		return true;

}

*/

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