学步园

#include <iostream>
#include <string.h>
using namespace std;
const int N = 102;
char a[N], b[N];
int dp[N][N];
int map[N][N];
void printLCS(int i,int j)
{
	if(i==0&&j==0)
		return;
	if(i==0)
	{
		printLCS(i,j-1);
		printf("%c",b[j-1]);//输出x,y时下标要减1，因为在记b（方向）的时候是从1开始的；
		return;
	}
	else if(j==0)
	{
		printLCS(i-1,j);
		printf("%c",a[i-1]);
		return;
	}
	if(map[i][j]==0)
	{
		printLCS(i-1,j-1);
		printf("%c",a[i-1]);
	}
	else if(map[i][j]==1)
	{
		printLCS(i-1,j);
		printf("%c",a[i-1]);
	}
	else
	{
		printLCS(i,j-1);
		printf("%c",b[j-1]);
	}
}
int main()
{
	while(cin >> a >> b)
	{
		int alen = strlen(a);
		int blen = strlen(b);
		memset(dp, 0, sizeof(dp));

		for(int i = 1; i <= alen; i++)
		{
			for(int j = 1; j <= blen; j++)
			{
				if(a[i - 1] == b[j -1])
				{
					dp[i][j] = dp[i-1][j-1] + 1;
					map[i][j] = 0; //xiexia
				}
				else
				{
					if(dp[i][j-1] > dp[i-1][j])
					{
						dp[i][j] = dp[i][j-1];
						map[i][j] = 2;//you
					}
					else
					{
						dp[i][j] = dp[i-1][j];
						map[i][j] = 1; //xia
					}
				}
			}
		}

		int L = dp[alen][blen];
		if(L == 0)
		{
			cout << a << b << endl;
			continue;
		}
		int cnt = 0;
		int x = alen;
		int y = blen;
		char com[N];
		memset(com, 0, sizeof(com));
		/*while(cnt < L)
		{
		if(map[x][y] == 0)
		{
		com[cnt++] = a[x-1];
		x = x -1;
		y = y -1;
		}
		else if(map[x][y] == 1)
		x = x -1;
		else
		y = y - 1;
		}*/
	printLCS(alen, blen);
	cout << endl;
		
	}
	return 0;
}