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>
#define rep(i,n) for (int i = 0; i < (n); ++i)
using namespace std;
typedef long long ll;


int main() {
    int q;
    cin>>q;
    
    while(1){
        //cout<<q<<endl;
        if(!q)break;
        string x,y;
        cin>>x>>y;
        int n=x.size();
        int m=y.size();
        int dp[1050][1050];
        for(int i=1;i<=m;i++){
            rep(j,n+1){
               dp[j][i]=0;
            }
        }
        for(int i=0;i<n;i++){
            for(int j=0;j<m;j++){
                if(x[i]==y[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[n][m]<<endl;
        q--;
    }
    
    
    return 0;
}

C++: #include<iostream>
#include<algorithm>
using namespace std;
int dp[1001][1001];
string s,t;
int n,m,a,ans;
int main(){
  cin>>a;
  for(int k=0;k<a;k++){
    cin>>s>>t;
    for(int i=0;i<=1000;i++)
      for(int j=0;j<=1000;j++)
    dp[i][j]=0;
    m=s.size();
    n=t.size();
    ans=0;
    for(int i=1;i<=m;i++){
      for(int j=1;j<=n;j++){
    if(s[i-1]==t[j-1]){
      dp[i][j]=dp[i-1][j-1]+1;
    }else{
      dp[i][j]=max(dp[i-1][j],dp[i][j-1]);
    }
      }
    } 
    cout<<dp[m][n]<<endl;
  }
  return 0;
}

C++: #include<iostream>
#include<string>
#include<algorithm>
using namespace std;

int lcs(string x, string y) {
	int m = x.size();
	int n = y.size();
	//cout<<m<<n<<endl;
	int maxl = 0;
	int A[1001][1001]={};
	x = ' ' + x;
	y = ' ' + y;
//	cout<<x<<y;
	for (int i = 0;i <= m;i++) {
		A[i][0] = 0;
	}
	for (int j = 0;j <= n;j++) {
		A[0][j] = 0;
	}

	for (int i = 1;i <= m;i++) {
		for (int j = 1;j <= n;j++) {
		//	cout<<x[i]<<y[j]<<endl;
			if (x[i] == y[j]) {
					A[i][j] = A[i-1][j-1] + 1;
			}
	     	else {
					A[i][j] = max(A[i - 1][j], A[i][j - 1]);
			}

			maxl = max(maxl, A[i][j]);
		}
		
	}
	return maxl;
}

int main() {
	int n;
	string x, y;
	cin >> n;
	for (int i = 0;i < n;i++) {
		cin >> x >> y;
		cout<<lcs(x, y)<<endl;
		//lcs(x,y);

	}
	return 0;
}

C++: #ifdef LOCAL_BUILD
#include "pch.h"
#define DLOG(msg) cout << "#" << __LINE__ << ":" << msg << endl;
#define DLOG_V(var)\
  cout << "#" << __LINE__ << ":" << #var << " : " << var << endl;
#else
#include <bits/stdc++.h>
#define DLOG(msg)
#define DLOG_V(var)
#endif
using namespace std;

constexpr auto no_value = numeric_limits<uint64_t>::max();

int solve(const string& str1, const string& str2) {
  int max_ = 0;
  vector<vector<int>> buf(str1.size(), vector<int>(str2.size(), 0));
  for (size_t j = 0; j < str2.size(); ++j) {
    for (size_t i = 0; i < str1.size(); ++i) {
      auto prev1 = j == 0 ? 0 : buf[i][j - 1];
      auto prev2 = i == 0 ? 0 : buf[i - 1][j];
      buf[i][j] = max(prev1, prev2);
      if (str1[i] == str2[j]) {
        auto p = i == 0 || j == 0 ? 0 : buf[i - 1][j - 1];
        buf[i][j] = max(buf[i][j], p + 1);
        max_ = max(max_, buf[i][j]);
      }
    }
  }
  return max_;
}

int main() {
  int n;
  cin >> n;
  for (int i = 0; i < n; ++i) {
    string str1;
    string str2;
    cin >> str1 >> str2;
    auto res = solve(str1, str2);
    cout << res << endl;
  }
}

C++: #include<iostream>
#include<algorithm>
#include<cmath>
#include<vector>
#include<string>
using namespace std;

int lcs(string s,string t)
{
  int c[1005][1005];
  int m=s.size(),n=t.size(),len=0;

  for(int i=0;i<=m;i++) c[i][0]=0;
  for(int i=0;i<=n;i++) c[0][i]=0;


  for(int i=1;i<=m;i++)
  {
    for(int j=1;j<=n;j++)
    {
      if(s.at(i-1)==t.at(j-1)) c[i][j]=c[i-1][j-1]+1;
      else c[i][j]=max(c[i-1][j],c[i][j-1]);

      len=max(len,c[i][j]);
    }
  }

  return len;
}

int main()
{
  int q;
  cin>>q;
  string s,t;
  for(int i=0;i<q;i++)
  {
    cin>>s>>t;
    cout<<lcs(s,t)<<endl;
  }
}

C++: #include <iostream>
#include <string>
#include <algorithm>
using namespace std;

static const int N=1000;

int Lcs(string X, string Y){
  int c[N+1][N+1];
  int LMAX=0;
  int m=X.size(), n=Y.size();

  X=' ' + X;
  Y=' ' + Y;

  for(int i=0; i<=m; i++) c[i][0]=0;
  for(int j=0; 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]);
      }
      LMAX=max(LMAX, c[i][j]);
    }
  }

  return LMAX;
}

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 <iostream>
#include <algorithm>
#include <vector>
#include <deque>
#include <queue>
#include <list>
#include <stack>
#include <string>
#include <tuple>
#include <functional>
#include <numeric>
#include <cmath>
#include <iomanip>
#include <map>
#include <random>
#include <cstdlib>
#define Loop(i, n) for(int i = 0; i < (int)n; i++)
#define Loop1(i, n) for(int i = 1; i <= (int)n; i++)
#define Loopr(i, n) for(int i = (int)n - 1; i >= 0; i--)
#define Loopr1(i, n) for(int i = (int)n; i >= 1; i--)
using namespace std;
typedef long long int ll;
 
string x, y;
int memo[1005][1005];
 
int dp(int a, int b) {
    if (memo[a][b] != INT_MIN) return memo[a][b];
    if (a == 0 || b == 0) memo[a][b] = 0;
    else if (x[a - 1] == y[b - 1]) {
        memo[a][b] = dp(a - 1, b - 1) + 1;
    }
    else {
        memo[a][b] = max(dp(a - 1, b), dp(a, b - 1));
    }
    return memo[a][b];
}
 
int main() {
    int q;
    cin >> q;
    Loop(i, q) {
        cin >> x >> y;
        Loop(j, x.size()+1) {
            Loop(k, y.size()+1) {
                memo[j][k] = INT_MIN;
            }
        }
        cout << dp(x.size(), y.size()) << endl;
    }
    return 0;
}

C++: #include<iostream>
#include<string>
#include<algorithm>
using namespace std;

string S,T;
int x[10000],y[10000];
int dp[10000][10000];
char U[27]="abcdefghijklmnopqrstuvwxyz";
int MAXN;

int main(){
	int q;
	cin>>q;
	for(int i=0;i<q;i++){
		MAXN=0;
		cin>>S>>T;
		for(int i=0;i<S.size();i++){
			for(int j=0;j<26;j++){
				if(S[i]==U[j]){
					x[i+1]=j;
				}
			}
		}
		for(int i=0;i<T.size();i++){
			for(int j=0;j<26;j++){
				if(T[i]==U[j]){
					y[i+1]=j;
				}
			}
		}
		for(int i=0;i<=T.size();i++){
			for(int j=0;j<=S.size();j++){
				if(i==0 || j==0){
					dp[i][j]=0;
				}
				else if(x[j]==y[i]){
					dp[i][j]=dp[i-1][j-1]+1;
				}
				else{
					dp[i][j]=max(dp[i][j-1],dp[i-1][j]);
				}
			}
		}
		for(int i=0;i<=T.size();i++){
			for(int j=0;j<=S.size();j++){
				MAXN=max(MAXN,dp[i][j]);
			}
		}
		cout<<MAXN<<endl;
	}
	return 0;
}