POJ

Common Subsequence

Time Limit: 1000MS Memory Limit: 10000KTotal Submissions: 55054 Accepted: 22947

Description

A subsequence of a given sequence is the given sequence with some elements (possible none) left out. Given a sequence X = < x1, x2, ..., xm > another sequence Z = < z1, z2, ..., zk > is a subsequence of X if there exists a strictly increasing sequence < i1, i2, ..., ik > of indices of X such that for all j = 1,2,...,k, x_ij = zj. For example, Z = < a, b, f, c > is a subsequence of X = < a, b, c, f, b, c > with index sequence < 1, 2, 4, 6 >. Given two sequences X and Y the problem is to find the length of the maximum-length common subsequence of X and Y.

Input

The program input is from the std input. Each data set in the input contains two strings representing the given sequences. The sequences are separated by any number of white spaces. The input data are correct.

Output

For each set of data the program prints on the standard output the length of the maximum-length common subsequence from the beginning of a separate line.

Sample Input

abcfbc         abfcabprogramming    contest abcd           mnp

Sample Output

420

题意：找最长上升子序列 只需按顺序即可

思路：dp[i][j]表示前一个串的前i个字母和后一个串的前j个字母的最长公共子序列的长度

#include <iostream>#include <cstdio>#include <algorithm>#include <cstring>#include <queue>#include <stack>#include <vector>#define max_ 1010#define inf 0x3f3f3f3f#define ll long longusing namespace std;int dp[max_][max_];int main(int argc, char const *argv[]){char s1[max_],s2[max_];while(scanf("%s%s",s1,s2)!=EOF){memset(dp,0,sizeof(dp));int i,j;for(i=1;i<=strlen(s1);i++){for(j=1;j<=strlen(s2);j++){if(s1[i-1]==s2[j-1])dp[i][j]=dp[i-1][j-1]+1;elsedp[i][j]=max(dp[i-1][j],dp[i][j-1]);}}printf("%d\n",dp[strlen(s1)][strlen(s2)]);}return 0;}