Go: package main

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

// define
var (
	sc = bufio.NewScanner(os.Stdin)
)

func bordersInt(in_map [][]int, invalid int) [][]int{
	H, W := len(in_map), len(in_map[0])
	out_map := make([][]int, H+2)
	for h:=0; h<H+2; h++ {
		out_map[h] = make([]int, W+2)
		for w:=0; w<W+2; w++ {
			out_map[h][w] = invalid
		}
	}
	for h:=0; h<H; h++{
		for w:=0; w<W; w++{
			out_map[h+1][w+1] = in_map[h][w] 
		}
	}
	return out_map
}

func bordersString(in_map [][]string, invalid string) [][]string{
	H, W := len(in_map), len(in_map[0])
	out_map := make([][]string, H+2)
	for h:=0; h<H+2; h++ {
		out_map[h] = make([]string, W+2)
		for w:=0; w<W+2; w++ {
			out_map[h][w] = invalid
		}
	}
	for h:=0; h<H; h++{
		for w:=0; w<W; w++{
			out_map[h+1][w+1] = in_map[h][w] 
		}
	}
	return out_map
}

func scanIntLine(len int) []int{
	arr := make([]int, len)
	for i:=0; i<len; i++{
		sc.Scan()
		tmp, err := strconv.Atoi(sc.Text())
		if err == nil{
			arr[i] = tmp
		}
	}
	return arr
}

func scanStringLine(len int) []string{
	arr := make([]string, len)
	for i:=0; i<len; i++{
		sc.Scan()
		arr[i] = sc.Text()
	}
	return arr
}

func scanIntSplit(len int) []int{
	arr := make([]int, len)
	sc.Scan()
	for i, v := range strings.Split(sc.Text(), " "){
		tmp, err := strconv.Atoi(v)
		if err == nil{
			arr[i] = tmp
		}
	}
	return arr
}

func maxInt(args... int) int{
	sort.Ints(args)
	return args[len(args)-1]
}

func main(){
	buf := make([]byte, 0)
    sc.Buffer(buf, 1000000009)
	var n int 
	fmt.Scan(&n)
	dp := make([][]int, 1003)
	for i:=0; i<1003; i++ {
		dp[i] = make([]int, 1003)
	}
	input_lines := scanStringLine(2*n)
	for i:=0; i<n; i++ {
		S, T := input_lines[2*i], input_lines[2*i+1]
		lenS, lenT := len(S), len(T)
		for i:=1; i<lenS+1; i++ {
			for j:=1; j<lenT+1; j++ {
				if S[i-1] == T[j-1] {
					dp[i][j] = dp[i-1][j-1]+1
				} else if S[i-1] != T[j-1] && dp[i-1][j] > dp[i][j-1] {
					dp[i][j] = dp[i-1][j]
				} else {
					dp[i][j] = dp[i][j-1]
				}
				// if S[i-1] == T[j-1] {
				// 	dp[i][j] = maxInt(dp[i-1][j-1]+1, dp[i-1][j], dp[i][j-1])
				// } else {
				// 	dp[i][j] = maxInt(dp[i-1][j], dp[i][j-1])
				// }
			}
		}
		fmt.Println(dp[lenS][lenT])
	}
}

C++: #include<iostream>
#include<string>
int main()
{
  int n;
  int an[1000];
  int l=0;
  std::cin>>n;
  std::string x;
  std::string y;
  int ans[1000][1000];
  int j,k;
  for(int i=0;i<n;i++){
    std::cin>>x;
    std::cin>>y;
    for(int j=0;j<1000;j++){
      for(int k=0;k<1000;k++){
	ans[j][k]=0;
      }
    }
    for(int j=0;j<x.size();j++){
      for(int k=0;k<y.size();k++){
	if(x[j]==y[k]){
	  ans[j][k]=ans[j-1][k-1]+1;
	}else{
	  if(ans[j][k-1]>ans[j-1][k]){
	    ans[j][k]=ans[j][k-1];
	  }else{
	    ans[j][k]=ans[j-1][k];
	  }
	}
      }
    }
    std::cout<<ans[x.size()-1][y.size()-1]<<'\n';  
  }
  return 0;
}

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

#if __has_include("print.hpp")
  #include "print.hpp"
#endif

#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()

typedef long long ll;
typedef pair<int, int> p;

int n, w;
vector<vector<int>> dp(500, vector<int>(10500, -1));
vector<int> vv;
vector<int> wv;

void solve(){
  for (int i = n - 1; i >= 0; i--) {
    for (int j = 0; j < w; j++) {
      if(j < wv[i]){
        dp[i][j] = dp[i+1][j];
      }else{
        dp[i][j] = max(dp[i+1][j], dp[i+1][j-wv[i]] + vv[i]);
      }
    }
  }
}

int main(){
  cin >> n >> w;
  for (int i = 0; i < n; i++)
  {
    int tmp1, tmp2;
    cin >> tmp1 >> tmp2;
    wv.push_back(tmp1);
    vv.push_back(tmp2);
  }

  solve();
  cout << dp[0][w] << endl;
}

C++: #include <iostream> 
#include <cstring> 
using namespace std;
int c[1001][1001];

int lcs(string x, string y)
{
    int maxl = 0;
    int m = x.length(), n = y.length();
 
    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 = 0; i < m; i++)
    {
        for (int j = 0; j < n; j++)
        {
            if (x[i] == y[j])
            { 
                if(i==0 || j==0) c[i][j] = 1;
                else c[i][j] = c[i-1][j-1] + 1; 
            }else
            {
                if(i==0 || j==0) c[i][j] = 0;
                else c[i][j] = max(c[i][j-1], c[i-1][j]);
            }
            maxl = max(maxl, c[i][j]);
        } 
    } 
    return maxl;
}

int main()
{
    
    //freopen("in1.txt","r",stdin);
    string x,y;
    int q;
    cin>>q;
    while(q--)
    {
        cin>>x>>y;
        int ans = lcs(x, y);
        cout<<ans<<endl;
    }
    return 0;
}

C++: #include<iostream>
#include<string>
using namespace std;
 
int main(){
  int c[1001][1001];
  string x,y;
  int n; cin >> n;
  while(n>0){
    n--;
    
    //文字列の入力
    cin >> x;
    cin >> y;

    //入力した文字列の長さをもとめる
    int lenx = x.size();
    int leny = y.size();
 
    //初期条件
    for(int i = 1; i <= lenx; i++){
      c[i][0] = 0;
    }
    
    //初期条件
    for(int j = 1; j <= leny; j++){
      c[0][j] = 0;
    }


    //LCS
    for(int i = 1; i <= lenx; i++){
      for(int j = 1; j <= leny; j++){
	//着目している文字が等しいとき
    if(x[i-1]==y[j-1]){
      c[i][j] = c[i-1][j-1] + 1;
      //着目している文字が等しくないときは
      //表の左と上の小さいほうを出力
    }else if(c[i-1][j] >= c[i][j-1]){
      c[i][j] = c[i-1][j];
    }else{
      c[i][j] = c[i][j-1];
    }
      }
    }
    
    //出力
    cout << c[lenx][leny] << endl;
  }
  return 0;
}

C++: /*
 * ALDS1_10_C.cpp
 *
 *  Created on: May 5, 2018
 *      Author: 13743
 */

#include<cstdio>
#include<cstring>
#include<algorithm>

int dp[1001][1001];
bool dpR[1001][1001];

int lcm(char* X, char* Y, int nx, int ny) {
	dp[1][1] = (X[0] == Y[0]);
	for(int i=1; i<=nx; i++) {
		for(int j=1; j<=ny; j++) {
			dp[i][j] = (X[i-1]==Y[j-1]) + dp[i-1][j-1];
			dp[i][j] = std::max(dp[i-1][j], dp[i][j]);
			dp[i][j] = std::max(dp[i][j-1], dp[i][j]);
		}
	}
	return dp[nx][ny];
}

int lcmRec(char* X, char* Y, int nx, int ny) {
	if(nx <=0 || ny <= 0) return 0;
	if(!dpR[nx][ny]) {
		dpR[nx][ny] = 1;
		dp[nx][ny] = lcmRec(X, Y, nx-1, ny-1) + (X[nx-1]==Y[ny-1]);
		dp[nx][ny] = std::max(lcmRec(X, Y, nx-1, ny), dp[nx][ny]);
		dp[nx][ny] = std::max(lcmRec(X, Y, nx, ny-1), dp[nx][ny]);
	}
	return dp[nx][ny];
}

int main() {
	int q;
	scanf("%d", &q);
	char X[1001];
	char Y[1001];
	while(q--) {
		scanf("%s", X);
		scanf("%s", Y);
		int nx = (int)strlen(X);
		int ny = (int)strlen(Y);
		//printf("%d\n", lcm(X, Y, nx, ny));
		printf("%d\n", lcmRec(X, Y, nx, ny));
	}
}

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

const int MAX_LENGTH = 1024;

char A[MAX_LENGTH + 1];
char B[MAX_LENGTH + 1];

int tu[MAX_LENGTH][MAX_LENGTH];

void lcs(int, int);

int main()
{
	int n;
	cin >> n;
	for (int i = 0; i < n; ++i)
	{
		cin >> A >> B;
		int lA = strlen(A), lB = strlen(B);
		lcs(lA, lB);
		cout << tu[lA][lB] << endl;
	}

}

void lcs(int lA, int lB)
{
	for (int i = 0; i < lA; ++i)
		tu[0][i] = 0;
	for (int i = 0; i < lB; ++i)
		tu[i][0] = 0;

	for (int i = 1; i <= lA; i++)
	{
		for (int j = 1; j <= lB; j++)
		{
			if (A[i-1] == B[j-1])
				tu[i][j] = tu[i - 1][j - 1] + 1;
			else
				tu[i][j] = max(tu[i][j - 1], tu[i - 1][j]);
		}
	}
}

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

static const int N = 1000;

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