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<iostream>
#include<algorithm>
#include<string>
using namespace std;

int Longest(string x, string y) {
  int L[1001][1001];
  int maxl = -1;
  int xlen = x.size();
  int ylen = y.size();

  x = ' ' + x;
  y = ' ' + y;

  for (int i = 1; i <= xlen; i++) L[i][0] = 0;
  for (int j = 1; j <= ylen; j++) L[0][j] = 0;

  for (int i = 1; i <= xlen; i++) {
    for (int j = 1; j <= ylen; j++) {
      if (x[i] == y[j]) {
        L[i][j] = L[i-1][j-1] + 1;
      } else {
        L[i][j] = max(L[i][j-1], L[i-1][j]);
        }
      maxl = max(maxl, L[i][j]);
    }
  }

  return maxl;
}

int main() {
  string X, Y;
  int n;
  cin >> n;

  for (int i = 0; i < n; i++) {
    cin >> X;
    cin >> Y;
    cout << Longest(X, Y) << endl;
  }

  


  return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define rep(i,n,x) for(int i=n;i<x;i++)
const int MAX_N = 1000;

int main() {
    int q; cin >> q;

    int dp[MAX_N+1][MAX_N+1];

    while(q > 0){
        string x, y; cin >> x >> y;

        int X = x.size(), Y = y.size();
        rep(i, 0, X){
            rep(j, 0, Y){
                if(x[i] == y[j]) dp[i+1][j+1] = dp[i][j] + 1;
                else dp[i+1][j+1] = max(dp[i][j+1], dp[i+1][j]);
            }
        }

        cout << dp[X][Y] << endl;

        q--;
    }

    return 0;
}

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

//#define int long long
//struct Fast {Fast(){cin.tie(0);ios::sync_with_stdio(0);}} fast;
//const int MOD = 1e9 + 7;
using intpair = pair<int, int>;

#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define reps(i, n, m) for (int i = (int)(n); i <= (int)(m); i++)
#define ALL(obj) (obj).begin(), (obj).end()
#define rALL(obj) (obj).rbegin(), (obj).rend()
#define ceiv(a, b) ((int)((a) + (b) - 1)/(int)(b))

int dp[1001][1001];

inline bool chmax(int &a, int b){
    if(a < b) a = b;
    return a < b;
}

signed main() {
    int Q; cin >> Q;
    while(Q--){
        string s, t;
        cin >> s >> t;
        int n = (int)s.length();
        int m = (int)t.length();
        
        rep(i,n+1)rep(j,m+1) dp[i][j] = 0;
        
        reps(i,1,n)reps(j,1,m){
            dp[i][j] = max(dp[i-1][j], dp[i][j-1]);
            if(s[i-1] == t[j-1]){
                chmax(dp[i][j], dp[i-1][j-1]+1);
            }
        }
        
        cout << dp[n][m] << endl;
    }
}

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

using namespace std;

static const int N = 1000;

static int lcs(string& s1, string& s2) {
	int table[N + 1][N + 1];
	int m = s1.size();
	int n = s2.size();
	int max_len = 0;
	s1 = ' ' + s1;
	s2 = ' ' + s2;

	for (int i = 0; i <= m; i++) table[i][0] = 0;
	for (int j = 0; j <= m; j++) table[0][j] = 0;
	for (int i = 1; i <= m; i++) {
		for (int j = 1; j <= n; j++) {
			if (s1[i] == s2[j]) {
				table[i][j] = table[i - 1][j - 1] + 1;
			}
			else {
				table[i][j] = max(table[i - 1][j], table[i][j - 1]);
			}

			max_len = max(table[i][j], max_len);
		}
	}

	return max_len;
}

int main() {
	int n;
	cin >> n;

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

	return 0;
}

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

int Longest(string x, string y) {
  int L[1001][1001];
  int maxl = -1;
  int xlen = x.size();
  int ylen = y.size();

  x = ' ' + x;
  y = ' ' + y;

  for (int i = 1; i <= xlen; i++) L[i][0] = 0;
  for (int j = 1; j <= ylen; j++) L[0][j] = 0;

  for (int i = 1; i <= xlen; i++) {
    for (int j = 1; j <= ylen; j++) {
      if (x[i] == y[j])
        L[i][j] = L[i-1][j-1] + 1;
      else
        L[i][j] = max(L[i][j-1], L[i-1][j]);

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

  return maxl;
}

int main() {
  string X, Y;
  int n;
  int result;

  cin >> n;

  for (int i = 0; i < n; i++) {
    cin >> X;
    cin >> Y;
    cout << Longest(X, Y) << endl;
  }

  


  return 0;
}

C++: #include <iostream>
#include <algorithm>
#include<string.h>
using namespace std;
int LCS(char *x,char *y);
char x[1001], y[1001];
int lcs[1001][1001];
int main()
{
	int q,i,j;

	cin >> q;
	for (i = 0; i < q; i++) {
		cin >> x;
		cin >> y;
		cout << LCS(x, y) << endl;
	}
}

int LCS(char *x, char *y)
{
	int i, j;
	int len_x, len_y;
	len_x = strlen(x);
	len_y = strlen(y);
	
	for (i = 1; i <+ len_x; i++) {
		for (j = 1; j <+ len_y; j++) {
			if (x[i-1] == y[j-1]) {
				lcs[i][j] = lcs[i - 1][j - 1] + 1;
				//printf("lcs[%d][%d]=%d\n", i, j, lcs[i - 1][j - 1] + 1);
			}
			if (x[i] != y[j]) {
				lcs[i][j] = max(lcs[i - 1][j], lcs[i][j - 1]);
				//printf("lcs[%d][%d]=%d\n", i, j, max(lcs[i - 1][j], lcs[i][j - 1]));
			}
		}
	//cout << endl;

	}
	for (i = 0; i < len_x; i++) {
		for (j = 0; j < len_y; j++) {
			//printf("%d ", lcs[i][j]);
		}
		//cout << endl;
	}
	//cout << "len_x=" << len_x << endl << "len_y=" << len_y << endl;
			
	return lcs[i-1][j-1];
}

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

using namespace std;

static const int N = 1000;
static int c[N + 1][N + 1] = {};

static int lcs(string& X, string& Y) {
  const size_t m(X.size());
  const size_t n(Y.size());
  X = ' ' + X;
  Y = ' ' + Y;

  int lcs = 0;
  
  for (size_t i = 1; i <= m; i++) {
    for (size_t 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]);
      }
      lcs = max(lcs, c[i][j]);
    }
  }
  return lcs;
}

int main() {
  int n;
  cin >> n;

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

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

int lcs(string X, string Y) {
  int dp[1000 + 1][1000 + 1];
  int max = 0;
  int m = X.size();
  int n = Y.size();
  X = ' ' + X;
  Y = ' ' + Y;
  for(int i = 1; i <= m; i++)
    dp[i][0] = 0;
  for(int i = 1; i <= n; i++)
    dp[0][i] = 0;
  for(int i = 1; i <= m; i++) {
    for(int j = 1; j <= n; j++) {
      if(X[i] == Y[j])
	dp[i][j] = dp[i - 1][j - 1] + 1;
      
      else if(dp[i - 1][j] >= dp[i][j - 1])
	dp[i][j] = dp[i - 1][j];
      
      else
	dp[i][j] = dp[i][j - 1];
      if(max < dp[i][j])
	max = dp[i][j];
    }
  }
  return max;
}

int main() {
  int N = 0;
  cin >> N;
  string X, Y;
  for(int i = 0; i < N; i++) {
    cin >> X >> Y;
    cout << (int)lcs(X, Y) << endl;
  }  return 0;
}