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;

typedef long long ll;
typedef pair<ll, ll> P;

#define pb push_back
#define rep(i, n) for(int i = 0; i < (n); i++)
#define FOR(i, a, n) for(int i = a; i < (n); i++)
#define mod (ll)(1e9+7)
#define int ll

__attribute__((constructor))
void initial() {
  cin.tie(0);
  ios::sync_with_stdio(false);
}

int lcs(string x, string y) {
  int c[1001][1001];
  int m = x.size(), n = y.size();
  int maxl = 0;
  x = ' ' + x, y = ' ' + y;
  for(int i = 0; i <= m; i++) c[i][0] = 0;
  for(int i = 1; i <= n; i++) c[0][i] = 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]);
      }
      maxl = max(maxl, c[i][j]);
    }
  }
  return maxl;
}

signed main() {
	ll n;
  string s1, s2;

  cin >> n;
  rep(i, n) {
    cin >> s1 >> s2;
    cout << lcs(s1, s2) << endl;
  }
}

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

void fnInput(vector<string>& rvsStrX, vector<string>& rvsStrY)
{
  int nMaxSiz;
  cin >> nMaxSiz;
  rvsStrX.resize(nMaxSiz);
  rvsStrY.resize(nMaxSiz);

  for (int i = 0; i < nMaxSiz; ++i)
  {
    cin >> rvsStrX[i] >> rvsStrY[i];
    rvsStrX[i] = ' ' + rvsStrX[i];
    rvsStrY[i] = ' ' + rvsStrY[i];
  }
}

int fnLngCmnSubseq(const vector<string>& cnrvsStrX, const vector<string>& cnrvsStrY)
{
  vector<vector<int>> vvnLcsDP;
  for (int i = 0; i < cnrvsStrX.size(); ++i)
  {
    const int nMAXNX = cnrvsStrX[i].size();
    const int nMAXNY = cnrvsStrY[i].size();

    vvnLcsDP.shrink_to_fit();
    vvnLcsDP.resize(nMAXNX, vector<int>(nMAXNY, 0));

    for (int nx = 1; nx < nMAXNX; ++nx)
      for (int ny = 1; ny < nMAXNY; ++ny)
        if (cnrvsStrX[i][nx] == cnrvsStrY[i][ny])
          vvnLcsDP[nx][ny] = vvnLcsDP[nx - 1][ny - 1] + 1;
        else
          vvnLcsDP[nx][ny] = max(vvnLcsDP[nx - 1][ny], vvnLcsDP[nx][ny - 1]);

    cout << vvnLcsDP[nMAXNX - 1][nMAXNY - 1] << endl;
  }
}

int main()
{
  cin.tie(0);
  ios::sync_with_stdio(false);
  vector<string> vsStrX, vsStrY;

  fnInput(vsStrX, vsStrY);
  fnLngCmnSubseq(vsStrX, vsStrY);
  return 0;
}

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

void fnInput(vector<string>& rvsStrX, vector<string>& rvsStrY)
{
  int nMaxSiz;
  cin >> nMaxSiz;
  rvsStrX.resize(nMaxSiz);
  rvsStrY.resize(nMaxSiz);

  for (int i = 0; i < nMaxSiz; ++i)
  {
    cin >> rvsStrX[i] >> rvsStrY[i];
    rvsStrX[i] = ' ' + rvsStrX[i];
    rvsStrY[i] = ' ' + rvsStrY[i];
  }
}

int fnLngCmnSubseq(const vector<string>& cnrvsStrX, const vector<string>& cnrvsStrY)
{
  vector<vector<int>> vvnLcsDP;
  for (int i = 0; i < cnrvsStrX.size(); ++i)
  {
    const int nMAXNX = cnrvsStrX[i].size();
    const int nMAXNY = cnrvsStrY[i].size();

    vvnLcsDP.clear();
    vvnLcsDP.resize(nMAXNX, vector<int>(nMAXNY, 0));

    for (int nx = 1; nx < nMAXNX; ++nx)
      for (int ny = 1; ny < nMAXNY; ++ny)
        if (cnrvsStrX[i][nx] == cnrvsStrY[i][ny])
          vvnLcsDP[nx][ny] = vvnLcsDP[nx - 1][ny - 1] + 1;
        else
          vvnLcsDP[nx][ny] = max(vvnLcsDP[nx - 1][ny], vvnLcsDP[nx][ny - 1]);

    cout << vvnLcsDP[nMAXNX - 1][nMAXNY - 1] << endl;
  }
}

int main()
{
  cin.tie(0);
  ios::sync_with_stdio(false);
  vector<string> vsStrX, vsStrY;

  fnInput(vsStrX, vsStrY);
  fnLngCmnSubseq(vsStrX, vsStrY);
  return 0;
}

C++: #include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
typedef long long ll;
using namespace std;

int main(){
    int q;
    cin>>q;
    string s1,s2;
    
    rep(i,q){
        cin>>s1>>s2;
        vector< vector< int > > c(1010, vector< int >(1010, 0));
        c[0][0]=0;
        rep(j,s1.length()+1)c[j][0]=0;
        rep(k,s2.length()+1)c[0][k]=0;
        for(int n=1;n<=s1.length();n++){
            for(int m=1;m<=s2.length();m++){
                if(s1[n-1]==s2[m-1])c[n][m]=c[n-1][m-1]+1;
                else {
                    c[n][m]=max(c[n-1][m],c[n][m-1]);
                }
            }
        }
        cout<<c[s1.length()][s2.length()]<<endl;
    }
}

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

int main() {

  int q;
  cin >> q;
  
  while (0 < q) {
    
    string X, Y;
    cin >> X >> Y;

    int x = X.size();
    int y = Y.size();

    // X_0 ... X_i と Y_0 ... Y_j に対するLCSの長さ
    vector<vector<int>> dp(x+1, vector<int>(y+1));

    int answer = 0;

    for (int i = 0; i < x; i++) {
      for (int j = 0; j < y; j++) {
        if (X[i] == Y[j]) {
          // 同じ文字列の場合は、
          // X_0 ... X_i と Y_0 ... Y_j に対するLCSに1加える
          dp[i+1][j+1] = dp[i][j] + 1;
        } else {
          // 違う場合は、
          // X_0 ... X_i と Y_0 ... Y_j+1 に対するLCSと
          // X_0 ... X_i+1 と Y_0 ... Y_j に対するLCSで
          // 大きい方
          dp[i+1][j+1] = max(dp[i][j+1], dp[i+1][j]);
        }
        answer = max(answer, dp[i+1][j+1]);
      }
    }

    cout << answer << endl;

    q--;
  }

  return 0;

}

C++: #include<iostream>
#include<algorithm>
#include<vector>
#include<string>
#include<cmath>
#include<cstdio>
#include<queue>
#include<deque>
#include<map>
#include<stack>
#include<set>
#include<utility>
using namespace std;
typedef pair<int,int> ii;
typedef long long ll;
typedef pair<ll,ii> P;
typedef unsigned long long int ull;
const int MOD=1e9+7;
int dy[]={1,0,-1,0};
int dx[]={0,1,0,-1};
const int MAXN=100000;
const int MAXE=100000;
const int MAXV=10000;
const ll INF=2e18;

int main(){
    int q;cin>>q;
    int dp[1001][1001];
    for(int k=0;k<q;k++){
        string s,t;cin>>s>>t;
        int n=(int)s.size();
        int m=(int)t.size();
        for(int i=0;i<=n;i++){
            for(int j=0;j<=m;j++){
                dp[i][j]=0;
            }
        }
        for(int i=0;i<n;i++){
            for(int j=0;j<m;j++){
                dp[i+1][j+1]=max(dp[i+1][j],dp[i][j+1]);
                if(s[i]==t[j]) dp[i+1][j+1]=max(dp[i+1][j+1],dp[i][j]+1);
            }
        }
        cout<<dp[n][m]<<endl;
    }
    return 0;
}

C++: #include <iostream>
#include <algorithm>
#include <cmath>

using namespace std;

int dp[1010][1010];



int solve() {

	string s,t;

	cin >> s >> t;


	int max_s = s.length();
	int max_t = t.length();

	memset(dp,0, sizeof(int) * 1010 * 1010);



	for (int i = 1; i <= max_s; i++) {
		for (int j = 1; j <= max_t; j++) {
			if (s.at(i - 1) == t.at(j -1)) {
				dp[i][j] = dp[i - 1][j - 1] + 1;
			} else {
				dp[i][j] = max(dp[i][j - 1],dp[i -1][j]);			
			}
		}
	}
	return dp[max_s][max_t];
}

int main() {
	int q;

	cin >> q;

	for (int i = 0; i  < q; i++) {
		cout << solve() << endl;
	}

}