Go: package main

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

const (
	initialBufSize = 100000
	maxBufSize     = 1000000
)

var sc *bufio.Scanner

func initScanner(r io.Reader) *bufio.Scanner {
	buf := make([]byte, initialBufSize)

	sc := bufio.NewScanner(r)
	sc.Buffer(buf, maxBufSize)
	sc.Split(bufio.ScanWords) // bufio.ScanLines
	return sc
}

func main() {
	sc = initScanner(os.Stdin)
	resolve()
}

func resolve() {
	n := scanInt(sc)
	results := []int{}
	for i := 0; i < n; i++ {
		results = append(results, resolveInstance())
	}
	for _, v := range results {
		fmt.Println(v)
	}
	return
}

func resolveInstance() int {
	x, y := scanString(sc), scanString(sc)
	lx, ly := len(x), len(y)
	dp := make([][]int, lx+1)
	dp[0] = make([]int, ly+1)
	for i := 1; i <= lx; i++ {
		dp[i] = make([]int, ly+1)
		dp[i][0] = dp[i-1][0]
		for j := 1; j <= ly; j++ {
			dp[i][j] = dp[i-1][j]
			if dp[i][j] < dp[i][j-1] {
				dp[i][j] = dp[i][j-1]
			}
			if x[i-1] == y[j-1] {
				cL := dp[i-1][j-1] + 1
				if dp[i][j] < cL {
					dp[i][j] = cL
				}
			}
		}
	}
	return dp[lx][ly]
}

const (
	remove = 0 + iota
	match
)

// snip-scan-funcs
func scanInt(sc *bufio.Scanner) int {
	sc.Scan()
	i, _ := strconv.Atoi(sc.Text())
	return int(i)
}
func scanString(sc *bufio.Scanner) string {
	sc.Scan()
	return sc.Text()
}

C++: #include<bits/stdc++.h>
using namespace std;
#define N 1050
int lc(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 n;cin>>n;
  while(n--){
    string s,v;cin>>s>>v;
    cout<<lc(s,v)<<endl;
  }
  return 0;
}

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=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;
  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<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++: // https://onlinejudge.u-aizu.ac.jp/status/users/uzi7215/submissions/1/ALDS1_10_C/judge/3551530/Python3
#include <iostream>
#include <vector>

int main(){
  int q;
  std::cin >> q;
  std::vector<std::string> x_list, y_list;
  for( int i=0; i<q; i++ ){
    std::string input;
    std::cin >> input;
    x_list.push_back( input );
    std::cin >> input;
    y_list.push_back( input );
  }

  for( int k=0; k<q; k++ ){
    std::string x = x_list[k];
    int m = x.size() + 1;
    std::string y = y_list[k];
    int n = y.size() + 1;
    std::vector< std::vector<int> > c(m, std::vector<int>(n, 0));

	int i, j;
    for( i=1; i<m; i++ ){
      for( j=1; j<n; j++ ){
      	if( i==0 or j==0){
      		c[i][j] = 0;
		}else if( x[i-1] == y[j-1] ){
          c[i][j] = c[i-1][j-1] + 1;
        }else{
          c[i][j] = std::max( c[i-1][j], c[i][j-1] );
        } 
      }
    }
    std::cout << c[m-1][n-1] << std::endl;
  }
}

C++: #include<iostream>
#include<string>
#include<algorithm>
using namespase 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 = 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() {
    string s1, s2;
    int n; cin >> n;
    for ( i = 0; i < n; i++ ){
        cin >> s1 >> s2;
        cout << lcs(s1, s2) << sndl;
    }
    
    return 0;
    
}

C++: #include <iostream>
#include <string>
#include <map>
#include <set>
#include <algorithm>
using namespace std;
#define MAX 100000

static const int N =100;

int lcs(string X,string Y){
  int c[N+1][N+1];
  int m=X.size();
  int n=Y.size();
  int ans=0;
  X= ' '+X;
  Y= ' '+Y;
  for(int i;i<=m;i++)c[i][0]=0;
  for(int j;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]);
      }
      ans=max(ans,c[i][j]);
    }
  
  }
  return ans;
}

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<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 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;
}

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

C++: #include <iostream>
#include <stdio.h>
#include <string>
#include <cmath>

#define MAX_LENGTH 1000
#define NIL -1
using namespace std;
//think easy make easy

int q;//num of datasets
string X;
string Y;
int map[MAX_LENGTH+1][MAX_LENGTH+1];

int findMaxLength(int x,int y){//x:Xの終端.y:Yの終端(0オリジン)
	int val;

	if(x < 0 || y < 0) return 0;

	if(map[x][y] == NIL){
		if(X.at(x) == Y.at(y)){
			val = findMaxLength(x-1,y-1) +1;
		}else{
			val = max(findMaxLength(x-1,y),findMaxLength(x,y-1));
		}
		map[x][y] = val;//メモ
		return val;
	}else return map[x][y];
}

int main(){
	
	scanf("%d",&q);

	for(int i=0;i<q;i++){
		cin >>X; cin >> Y;
		for(int i=0;i<X.size();i++){
			for(int j=0;j<Y.size();j++){
				map[i][j] = NIL;
			}
		}
	
		cout <<findMaxLength(X.size()-1,Y.size()-1) <<endl;
	}

	return 0;
}