Go: package main

import "fmt"

func initialize_grid(width int,height int)[][]int{
	var grid [][]int
	for i:=0;i<height+1;i++{
		var grid_row  []int
		for j:=0;j<width+1;j++{
			grid_row = append(grid_row,0)
		}
		grid = append(grid,grid_row[:])
	}
	return grid
}

func ma(x int,y int)int{
	if x >= y{
		return x
	}else{
		return y
	}
}

func main()  {
	//Take input
	var num int
	var st1,st2 string
	var string_pairs [][]string
	fmt.Scan(&num)
	for i:=0;i<num;i++{
		var string_pair []string
		fmt.Scan(&st1)
		fmt.Scan(&st2)
		string_pair = append(string_pair,st1,st2)
		string_pairs = append(string_pairs,string_pair)
	}
	//DP
	//initialize grid
	for i:=0;i<num;i++{
		string_1 := string_pairs[i][0]
		string_2 := string_pairs[i][1]

		dp := initialize_grid(len(string_2),len(string_1))

		for j:=1;j<len(string_1)+1;j++{
			for k:=1;k<len(string_2)+1;k++{
				if string_1[j-1] == string_2[k-1]{
					dp[j][k] = dp[j-1][k-1] + 1
				}else{
					dp[j][k] = ma(dp[j-1][k],dp[j][k-1])
				}
			}
		}
		fmt.Println(dp[len(string_1)][len(string_2)])
	}
}

C++: #include <bits/stdc++.h>

using namespace std;
int main(int argc, const char * argv[]) {
    int q, i, m, n, sl1, sl2;
    cin >> q;
    vector<string> strlist;
    string str, str1, str2;
    for(i = 0;i < q;i++){
        cin >> str;
        strlist.push_back(str);
        cin >> str;
        strlist.push_back(str);
    }
    
    //start
    for(i = 0;i < q*2;i += 2){
        str1 = strlist[i];
        sl1 = str1.length();
        str2 = strlist[i+1];
        sl2 = str2.length();
        int dp[sl1+1][sl2+1];
        for(m = 0;m <= sl2;m++){
            dp[0][m] = 0;
        }
        for(m = 0;m <= sl1;m++){
            dp[m][0] = 0;
        }
        for(m = 1;m <= sl1;m++){
            for(n = 1;n <= sl2;n++){
                dp[m][n] = 0;
            }
        }
        for(m = 1;m <= sl1;m++){
            for(n = 1;n <= sl2;n++){
                if(str1[m-1] == str2[n-1]){
                    dp[m][n] = dp[m-1][n-1] + 1;
                }else{
                    dp[m][n] = max(dp[m-1][n], dp[m][n-1]);
                }
            }
        }
        m = sl1;
        n = sl2;
        printf("%d\n", dp[m][n]);
        
    }
    return 0;
}

C++: #include<iostream>
#include<cmath>
#include<vector>
#include<string>

using namespace std;
#define ML 1000

inline int comp_char(char a,char b) { if(a==b) return 1;else return 0;}


int longest_cmmsubseq(string &xcomp,string &ycomp,vector<vector<int>> &memo){
  int ysize=ycomp.size();
  int xsize=xcomp.size();
  int max=0;
  for(int i=0;i<xsize;i++){
    if(ycomp.at(0)==xcomp.at(i)){
      while(i<xsize){ memo.at(i).at(0)=1; i++;}
      continue;
    }
    else memo.at(i).at(0)=0;
  }
  for(int j=0;j<ysize;j++){
    if(ycomp.at(j)==xcomp.at(0)){
      while(j<ysize){ memo.at(0).at(j)=1; j++;}
      continue;
    }
    else memo.at(0).at(j)=0;
  }

  for(int j=1;j<ysize;j++){
    for(int i=1;i<xsize;i++){
      max=memo.at(i-1).at(j-1)+comp_char(xcomp.at(i),ycomp.at(j));
      if(max<memo.at(i-1).at(j)) max=memo.at(i-1).at(j);
      if(max<memo.at(i).at(j-1)) max=memo.at(i).at(j-1);
      memo.at(i).at(j)=max;
      max=0;
    }
  }
  return memo.at(xsize-1).at(ysize-1);
}

int main(void){

  int size;
  cin>>size;

  vector<vector<int>> memo(ML,vector<int>(ML));
  string xcomp,ycomp;
  for(int i=0;i<size;i++){
    cin>>xcomp>>ycomp;
    cout<<longest_cmmsubseq(xcomp,ycomp,memo)<<endl;
  }
}

C++: #include <iostream>                                          
#include <string>                                            

using namespace std;                                         
                                                             
//L[i][j] X[0]..X[i]??¨X[0]..Y[j]???LCS                        
int L[1000][1000]={};                                        
int main(){
  int testnum;
  cin>>testnum;                                              
  for(int t=0;t<testnum;++t){                                
    string X,Y;                                              
    cin>>X>>Y;
    
    for(int i=1;i<=X.length();++i){                          
      for(int j=1;j<=Y.length();++j){                        
        if(X[i-1]==Y[j-1])
          L[i][j] = 1 + L[i-1][j-1];                         
        else
          L[i][j] = max(L[i][j-1],L[i-1][j]);
      }
    }

    cout << L[X.length()][Y.length()] << endl;
  }
 
  return 0;
}

C++: #include<iostream>
#include<string>
#include<algorithm>
using namespace std;
static const int N = 1000; // 読み取り専用（書き換え不可)

int lcs(string X, string Y){
    int c[N+1][N+1];
    int m = X.size();
    int n = Y.size();
    int maxv = 0;
    X = ' ' + X; //X[0]に空白を挿入
    Y = ' ' + Y; //Y[0]に空白を挿入
    for(int i=0;i<=m;i++){
        c[i][0] =0;
    }
    for(int j=1;j<=n;j++){
        c[0][j] =0; 
    }
    for(int i = 1;i<=m;i++){
        for(int j=1;j<=n;j++){
            if(X[i] == Y[j]){
                c[i][j] = c[i-1][j-1]+1;
            }
            else{
                c[i][j] = max(c[i-1][j],c[i][j-1]);
            }
         maxv = max(maxv,c[i][j]);   
        } 
    }
    return maxv;
}

int main(){
    string s1,s2;
    int n; 
    cin >> n;
    for(int i=0;i<n;i++){
        cin >> s1 >> s2;
        cout << lcs(s1,s2) << endl;
    }
    return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
#define int long long

signed main(){
  cin.tie(0);
  ios::sync_with_stdio(false);

  int n; cin >> n;
  while( n-- ) {
    string s,t; cin >> s >> t;
    int N = max(s.size(),t.size());
    vector< vector<int> > dp(N+1,vector<int>(N+1,0));
    for(int i = 0; i < s.size(); i++){
      for(int j = 0; j < t.size(); j++){
        if(s[i] == t[j]) dp[i+1][j+1] = dp[i][j] + 1;
        else dp[i+1][j+1] = max(dp[i+1][j],dp[i][j+1]);
      }
    }
    cout << dp[s.size()][t.size()] << endl;
  }

  return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef pair<ll,ll> pl;
typedef vector<pl> vp;
#define fore(i,a,b) for(ll i=(a);i<=(b);++i)
#define rep(i,n) fore(i,0,(n)-1)
#define rfore(i,a,b) for(ll i=(b);i>=(a);--i)
#define rrep(i,n) rfore(i,0,(n)-1)
#define all(x) (x).begin(),(x).end()
const ll INF=1001001001;
const ll LINF=1001001001001001001;
const ll D4[]={0,1,0,-1,0};
const ll D8[]={0,1,1,0,-1,-1,1,-1,0};
template<class T>
bool chmax(T &a,const T &b){if(a<b){a=b;return 1;}return 0;}
template<class T>
bool chmin(T &a,const T &b){if(b<a){a=b;return 1;}return 0;}

void solve(){
    ll n;cin>>n;
    while(n--){
        string s,t;cin>>s>>t;
        ll l1=s.size(),l2=t.size();
        vvl dp(l1+1,vl(l2+1));
        rep(i,l1)rep(j,l2){
            dp[i+1][j+1]=max(dp[i][j+1],dp[i+1][j]);
            if(s[i]==t[j])dp[i+1][j+1]=dp[i][j]+1;
        }
        cout<<dp[l1][l2]<<endl;
    }
}

int main(){
    cin.tie(0);
    ios::sync_with_stdio(0);
    solve();
}