最长公共子序列。
#pragma comment(linker, "/STACK:1024000000,1024000000")
#include<cstdio>
#include<cstring>
#include<cmath>
#include<algorithm>
#include<vector>
#include<map>
#include<set>
#include<queue>
#include<stack>
#include<iostream>
using namespace std;
typedef long long LL;
const double pi=acos(-1.0),eps=1e-;
void File()
{
freopen("D:\\in.txt","r",stdin);
freopen("D:\\out.txt","w",stdout);
}
inline int read()
{
char c = getchar(); while(!isdigit(c)) c = getchar();
int x = ;
while(isdigit(c)) { x = x * + c - ''; c = getchar(); }
return x;
} const int maxn=;
char s[maxn],t[maxn];
int dp[maxn][maxn]; int main()
{
while(~scanf("%s%s",s,t))
{
memset(dp,,sizeof dp);
int lens=strlen(s),lent=strlen(t),ans=;
for(int i=;i<lens;i++)
{
for(int j=;j<lent;j++)
{
if(s[i]==t[j]) dp[i+][j+]=dp[i][j]+;
else dp[i+][j+]=max(dp[i][j+],dp[i+][j]);
ans=max(dp[i+][j+],ans);
}
}
printf("%d\n",ans);
}
return ;
}