题目地址：http://acm.hdu.edu.cn/showproblem.php?pid=1503
求出LCS，然后根据d[][]找出路径，注意要从后往前找，而不能从前往后找
#include <iostream>
#include <algorithm>
#include <cstring>
#include <cstdio>
using namespace std;
const int maxn=100+5;
char str1[maxn],str2[maxn];
int d[maxn][maxn];
void Print(int x,int y){if(x>=1&&d[x-1][y]==d[x][y]) {Print(x-1,y);cout<<str1[x];}else if(y>=1&&d[x][y-1]==d[x][y]){Print(x,y-1);cout<<str2[y];}else if(x>=1&&y>=1&&d[x][y]-d[x-1][y-1]==1){Print(x-1,y-1);cout<<str1[x];}
}
int main(int argc, char const *argv[])
{while(scanf("%s%s",str1+1,str2+1)!=EOF){int len1=strlen(str1+1),len2=strlen(str2+1);d[0][0]=0;for(int i=1;i<=len1;i++)for(int j=1;j<=len2;j++)if(str1[i]==str2[j]) d[i][j]=d[i-1][j-1]+1;else d[i][j]=max(d[i-1][j],d[i][j-1]);Print(len1,len2);cout<<endl; }return 0;
}