Go: package main

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

var (
	nstr   func() string
	stdout *bufio.Writer
)

func init() {
	nstr = newReadString(os.Stdin)
	stdout = bufio.NewWriter(os.Stdout)
}

func main() {
	defer stdout.Flush()

	n := nint()
	xList := make([]string, n)
	yList := make([]string, n)

	for i:=0;i<n ;i++  {
		xList[i] = nstr()
		yList[i] = nstr()
	}

	for i := 0; i<n	; i++  {
		fmt.Println(lcs(xList[i], yList[i]))
	}

}

func lcs(x string, y string) int{
	var m = len(x)
	var n = len(y)

	c := make([][]int, m+1)
	for i:= range c{
		c[i] = make([]int, n+1)
	}
	for i:=	1;i<=m ;i++  {
		for j:=1;j<=n ;j++  {
			if x[i-1] == y[j-1]{
				c[i][j] = c[i-1][j-1] + 1
			}else{
				c[i][j] = int(math.Max(float64(c[i-1][j]), float64(c[i][j-1])))
			}


		}
	}
	return c[m][n]

}


func newReadString(ior io.Reader) func() string {
	r := bufio.NewScanner(ior)
	r.Buffer(make([]byte, 1024), int(1e+11))
	r.Split(bufio.ScanWords)

	return func() string {
		if !r.Scan() {
			panic("Scan failed")
		}
		return r.Text()
	}
}

func nint64() int64 {
	i, err := strconv.ParseInt(nstr(), 0, 64)
	if err != nil {
		panic(err.Error())
	}
	return i
}

func nint() int {
	return int(nint64())
}

func getIntSlice(n int) []int {
	b := make([]int, n)
	for i := 0; i < n; i++ {
		b[i] = nint()
	}
	return b
}

func getStringSlice(n int) []string {
	b := make([]string, n)
	for i := 0; i < n; i++ {
		b[i] = nstr()
	}
	return b
}

func gcd(x, y int) int {
	if y == 0 {
		return x
	}
	return gcd(y, x%y)
}

func lcm(x, y int) int {
	return x * y / gcd(x, y)
}

func contains(s []int, e int) bool {
	for _, a := range s {
		if a == e {
			return true
		}
	}
	return false
}

func bin(i int, prefix bool) string {
	i64 := int64(i)

	if prefix {
		return "0b" + strconv.FormatInt(i64, 2)
	} else {
		return strconv.FormatInt(i64, 2)
	}
}

func strReverse(s string) string {
	runes := []rune(s)
	for i, j := 0, len(runes)-1; i < j; i, j = i+1, j-1 {
		runes[i], runes[j] = runes[j], runes[i]
	}

	return string(runes)
}

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

int lcs(string a,string b){
  int c[1001][1001];
  for(int i=0;i<1001;i++){
      for(int j=0;j<1001;j++){
          c[i][j]=0;    
      } 
  }
  int m=a.size(),n=b.size();
  int mx=0;
  a=' '+a;
  b=' '+b;
  for(int i=1;i<=m;i++){
    for(int j=1;j<=n;j++){
      if(a[i]==b[j]){
	c[i][j]=c[i-1][j-1]+1;
      }else{
	c[i][j]=max(c[i-1][j],c[i][j-1]);
      }
      mx=max(mx,c[i][j]);
    }
  }
  return mx;
}


int main(){
  int q;
  string s1,s2;
  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;
#define N 1050
int lcs(string X,string Y){
  int c[N+1][N+1];
  int m = X.size();
  int n = Y.size();
  int maxl = 0;
  X = ' ' + X;
  Y = ' ' + Y;
  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]);
      maxl=max(maxl,c[i][j]);
    }
  }
  return maxl;
}
int main(){
  int q;cin>>q;
  while(q--){
    string a,b;cin>>a>>b;
    cout<<lcs(a,b)<<endl;
  }
  return 0;
}

C++: #include <iostream>

using namespace std;

int lcs(string X, string Y) {
  int memo[1010][1010];
  int maxl = 0;

  // 初期化、境界条件を考慮して場合分け
  for (int i = 0; i < X.size(); i++) {
    if (X[i] == Y[0]) {
      memo[i][0] = 1;
    } else {
      memo[i][0] = 0;
    }
  }

  for (int j = 0; j < Y.size(); j++) {
    if (X[0] == Y[j]) {
      memo[0][j] = 1;
    } else {
      memo[0][j] = 0;
    }
  }

  for (int i = 0; i < X.size(); i++) {
    for (int j = 0; j < Y.size(); j++) {
      if (X[i] == Y[j]) {
        memo[i][j] = memo[i-1][j-1] + 1;
      } else {
        memo[i][j] = max(memo[i-1][j], memo[i][j-1]);
      }
      maxl = max(maxl, memo[i][j]);
      //cout << i << "," << j << "," << X[i] << "," << Y[j] << "," << maxl << endl;
    }
  }
  return maxl;
}

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

C++: #include <cstdio>
#include <cstring>
#include <algorithm>

using namespace std;

const int kMax = 1000 + 10;

char a_str[kMax], b_str[kMax];
int dp[kMax][kMax];

int main() {
    int q;
    scanf("%d", &q);
    while(q --) {
        scanf("%s%s", a_str, b_str);
        int n = strlen(a_str), m = strlen(b_str);
        for(int i = 0;i < n;++ i) {
            for(int j = 0;j < m;++ j) {
                if(a_str[i] == b_str[j]) dp[i][j] = (i && j ? (dp[i-1][j-1] + 1) : 1);
                else dp[i][j] = max(i ? dp[i-1][j] : 0, j ? dp[i][j-1] : 0);
            }
        }
        printf("%d\n", dp[n-1][m-1]);
    }
    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
int LCS(string &X, string &Y) {
  X = " " + X;
  Y = " " + Y;
  int X_size = X.size(), Y_size = Y.size();
  vector<vector<int>> CS(Y_size, vector<int>(X_size, 0));
  for (int i = 0; i < Y_size; i++) {
    for (int j = 0; j < X_size; j++) {
      if (i == 0 || j == 0) continue;
      else if (X[j] == Y[i]) {
        CS[i][j] = CS[i - 1][j - 1] + 1;
      } else {
        CS[i][j] = max(CS[i][j - 1], CS[i - 1][j]);
      }
    }
  }
  return CS[Y_size - 1][X_size - 1];
}
int main() {
  int q;
  cin >> q;
  string X, Y;
  for (size_t i = 0; i < q; i++) {
    cin >> X >> Y;
    cout << LCS(X, Y) << endl;

    X.clear();
    Y.clear();
  }
}

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

int dp[1005][1005];
int q,n,m;
string x,y;

int main() {
	cin >> q;
	for(int a = 0; a < q; a++){
		cin >> x >> y;
		n = x.size();
		m = y.size();
		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 if (x[i] != y[j]) dp[i+1][j+1] = max(dp[i][j+1],dp[i+1][j]);
			}
		}
		cout << dp[n][m] << 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 m=X.size();
  int n=Y.size();
  int maxl=0;
  X= ' ' + X;
  Y= ' ' + Y;
 
  for(int i=1;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]);
      }
      maxl=max(maxl,c[i][j]);
    }
  }
  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 <bits/stdc++.h>
using namespace std;

int main(){
        int q;
        cin >> q;
        for(int k = 0; k < q; k++){
                string x, y;
                cin >> x >> y;
                int n = x.size(), m = y.size();
                int l[n + 1][m + 1];
                for(int j = 0; j <= m; j++){
                        for(int i = 0; i <= n; i++){
                                if(i == 0 || j == 0) l[i][j] = 0;
                                else if(x[i - 1] == y[j - 1]) l[i][j] = 1 + l[i - 1][j - 1];
                                else l[i][j] = max(l[i - 1][j], l[i][j - 1]);
                        }
                }
                cout << l[n][m] << endl;
        }
        return 0;
}