poj 1458 Common Subsequence 最基本的LCS 最长公共子序列

刚好对应算法导论 15.4 最长公共子序列

#include <iostream>
#include <stdio.h>
#include <cstring>

using namespace std;


string strA,strB;
#define MAX_N (2000+1)
unsigned short  dp[MAX_N][MAX_N]; 

int lcs(string stra,string strb)
{
	int la=stra.length();
	int lb=strb.length();

	dp[0][0]=0;
	for(int i=0;i<la;i++)
		dp[i][0]=0;
	for(int j=0;j<lb;j++)
		dp[0][j]=0;

	for(int i=0;i<la;i++)
	{
		for(int j=0;j<lb;j++)
		{
			int rel_i = i+1;
			int rel_j = j+1;
			if(stra[i] == strb[j])
			{
				dp[rel_i][rel_j] = dp[rel_i-1][rel_j-1] + 1;
			}
			else
			{
				dp[rel_i][rel_j] = max(dp[rel_i-1][rel_j],dp[rel_i][rel_j-1]);
			}
		}
	}

	return dp[la+1-1][lb+1-1];

}
int main()
{
	while(cin>>strA>>strB)
	{
		//cout<<"strA:"<<strA<<"strB:"<<strB<<endl;
		cout<<lcs(strA,strB)<<endl;
	}
}