DFS最长公共子序列

//最长公共子序列

//a123b4c
//1234abc
#include 
#include 
using namespace std;

string dfs(string str1,string str2)
{
	
	int len1=str1.length(); 
	int len2=str2.length(); 
	string ans;
	for(int i=0;i>s1>>s2;
	cout<