Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

//Util
func nextStr() string {
	sc.Scan()
	return sc.Text()
}

func nextInt() int {
	sc.Scan()
	i, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}
	return i
}

func maxInt(a, b int) int {
	if a > b {
		return a
	} else {
		return b
	}
}

func minInt(a, b int) int {
	if a > b {
		return b
	} else {
		return a
	}
}

func absInt(a int) int {
	if a >= 0 {
		return a
	} else {
		return -a
	}
}

func absFloat64(a float64) float64 {
	if a >= 0 {
		return a
	} else {
		return -a
	}
}

func minFloat64(a, b float64) float64 {
	if a > b {
		return b
	} else {
		return a
	}
}

func str2Int(s string) int {
	n, _ := strconv.Atoi(s)
	return n
}

//Main
var sc = bufio.NewScanner(os.Stdin)
var q int
var X, Y string

func lcs(X, Y string) int {
	lenX := len(X)
	lenY := len(Y)
	dp := make([][]int, lenX+1)
	for i := 0; i < lenX+1; i++ {
		dp[i] = make([]int, lenY+1)
	}

	res := 0
	for i := 1; i < lenX+1; i++ {
		for j := 1; j < lenY+1; j++ {
			if X[i-1] == Y[j-1] {
				dp[i][j] = dp[i-1][j-1] + 1
			} else {
				dp[i][j] = maxInt(dp[i-1][j], dp[i][j-1])
			}
			//fmt.Println(dp)
			res = maxInt(res, dp[i][j])
		}

	}
	return res
}

func main() {
	sc.Split(bufio.ScanWords)
	q = nextInt()

	for i := 0; i < q; i++ {
		X = nextStr()
		Y = nextStr()

		fmt.Println(lcs(X, Y))
	}
}

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

static const int N = 1000;

int lcs(string X,string Y){
    int c[N+1][N+1];    //c[i][k]???Xi??¨Yk???LCS??¨??????????????????
    int m = X.size();
    int n = Y.size();
    int maxl = 0;
    X = ' ' + X; // X[0]?????????????????\
    Y = ' ' + Y;
    for(int i=1;i<=m;i++) c[i][0] = 0;
    for(int k=1;k<=n;k++) c[0][k] = 0;

    for(int i=1;i<=m;i++){
        for(int k=1;k<=n;k++){
            if(X[i]==Y[k]){
                c[i][k] = c[i-1][k-1] + 1;
            } else {
                c[i][k] = max(c[i-1][k],c[i][k-1]);
            }
            maxl = max(maxl,c[i][k]);
        }
    }

    return maxl;
}

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<vector>
//#include<algorithm>

const static int MAX = 1001;
std::string X, Y;
int LCS[MAX][MAX];

int main(void){
    int q, x_size, y_size;
    std::cin >> q;
    for(int i = 0; i < q; i++){
	std::cin >> X >> Y;
	LCS[0][0] = 0;
	LCS[0][1] = 0;
	LCS[1][0] = 0;
	x_size = X.size();
	y_size = Y.size();
	for(int j = 0; j < X.size(); j++){
	    for(int k = 0; k < Y.size(); k++){
		if(X[j] == Y[k]){
		    LCS[j+1][k+1] = LCS[j][k] + 1;
		}else if(X[j] != Y[k]){
		    LCS[j+1][k+1] = std::max(LCS[j][k+1], LCS[j+1][k]);
		}
	    }
	}
	std::cout << LCS[x_size][y_size] << std::endl;
    }

    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define ll long long
#define vl vector<ll>
#define pl pair<ll,ll>
#define rep(i,b) for(ll i=0;i<b;i++)
#define all(v) (v).begin(),(v).end()

ll lcs(string X,string Y){
    ll c[1001][1001];
    ll m=X.size();
    ll n=Y.size();
    ll maxl=0;
    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]);
        }
        maxl=max(maxl,c[i][j]);
        }
    }
    return maxl;
}

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

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

static int N=1000;

int lcs(string x,string y){
  int num[N+5][N+5];
  int ans=0;
  int leng_x=x.size();
  int leng_y=y.size();  
  
  x=' '+x;
  y=' '+y;

  for(int i=1;i<=leng_x;i++)num[i][0]=0;
  for(int i=1;i<=leng_y;i++)num[0][i]=0;
  

  for(int i=1;i<=leng_x;i++){
    for(int j=1;j<=leng_y;j++){
      if(x[i]==y[j]) num[i][j]=num[i-1][j-1]+1;
      else num[i][j]=max(num[i][j-1],num[i-1][j]);
      ans=max(ans,num[i][j]);
    }
  }
  return ans;
}

int main(){
  string s1,s2;
  int q;

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

  return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
inline void chmax (int& a, int b) {
  if (a < b) a = b;
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int q;
  cin >> q;
  while (q--) {
    string x, y;
    cin >> x >> y;
    int m = x.length();
    int n = y.length();
    vector<int> dp(n + 1, 0);
    for (int i = 1; i <= m; i++) {
      for (int j = 1; j <= n; j++) {
        chmax(dp[j], dp[j - 1]);
        if (x[i - 1] == y[j - 1]) dp[j] = dp[j - 1] + 1;
      }
    }
    int ret = dp[n];
    cout << ret << '\n';
  }
  return 0;
}