Go: package main

import (
	. "fmt"
    "math"
)

// func init() { Println("----------------------------------------") }

func main() {
    const L_MAX = 1003

	var q int
	Scanf("%d", &q)
	X := make([]string, 0, 150)
	Y := make([]string, 0, 150)
	for i := 0; i < 2 * q; i++ {
	    var tmp string
	    Scanf("%s", &tmp)

	    if i % 2 == 0 {
	        X = append(X, tmp)
	    } else {
	        Y = append(Y, tmp)
	    }
	}

    for i := 0; i < q; i++ {
        dp := make([][]int, L_MAX)
        for k, _ := range dp {
            dp[k] = make([]int, L_MAX)
        }

        x, y := X[i], Y[i]

        // init
        isXFound := false
        for c := 0; c < len(x); c++ {
            if isXFound || y[0] == x[c] {
                dp[0][c] = 1
                isXFound = true
            }
        }
        isYFound := false
        for r := 0; r < len(y); r++ {
            if isYFound || x[0] == y[r] {
                dp[r][0] = 1
                isYFound = true
            }
        }

        for r := 1; r < len(y); r++ {
            for c := 1; c < len(x); c++ {
                // dp[r][c]
                if x[c] == y[r] {
                    dp[r][c] = int(math.Max(float64(dp[r - 1][c - 1] + 1), float64(dp[r][c])))
                }

                dp[r][c] = int(math.Max(float64(dp[r][c]), math.Max(float64(dp[r - 1][c]), float64(dp[r][c - 1]))))
            }
        }
        Println(dp[len(y) - 1][len(x) - 1])

        // LCSも求めておく
        // ans := ""
        // r, c := len(y) - 1, len(x) - 1
        // for r >= 0 && c >= 0 {
        //     if y[r] == x[c] {
        //         ans = string(x[c]) + ans
        //         r--
        //         c--
        //     } else {
        //         if dp[r - 1][c] > dp[r][c - 1] {
        //             r--
        //         } else {
        //             c--
        //         }
        //     }
        // }
        // Println(ans)
    }
}

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--) {
		for(int i=0; i<1001; i++) {
			for(int j=0; j<1001; j++) {
				dpR[i][j] = dp[i][j] = 0;
			}
		}
		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 <vector>
#include <cmath>
#include <algorithm>
#include <string>
#include <sstream>
#include <utility>
#define ll long long int
#define rep(i,x,y) for(int i=x;i<y;i++)
#define rel(i,x,y) for(int i=x-1;i>=y;i--)
#define all(x) x.begin(),x.end()
#define mod 1000000007
using namespace std;

int main(){
	int q;
	cin >> q;
	string X[q],Y[q];
	rep(i,0,q){
		cin >> X[i];
		cin >> Y[i];
	}

	rep(i,0,q){
		int m = X[i].length();
		int n = Y[i].length();
		int dp[m+1][n+1] = {};
		int maxl=0;
		rep(j,0,m){
			rep(k,0,n){
				if(X[i][j] == Y[i][k]) dp[j+1][k+1] = dp[j][k]+1;
				else dp[j+1][k+1] = max(dp[j][k+1],dp[j+1][k]);
			}
		}
		cout << dp[m][n] << 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<string>
#include<algorithm>
using namespace std;
static const int N = 1001;

int lcs(string X, string Y){
    int c[N][N];
    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(){
    int q;
    cin >> q;
    while(q--){
        string a,b; cin >> a >> b;
        cout << lcs(a,b) << endl;
    }
}

C++: #include <iostream>

using namespace std;

typedef long long signed int ll;

constexpr ll NIL = -20000000000;

string s[2];
int dp[1001][1001];

int lcs(int x,int y) {
    if(x < 0 || y < 0) return 0;
    if(x >= s[0].size() || y >= s[1].size()) return 0;
    if(dp[x][y] == -1) {
        dp[x][y] = max(lcs(x+1,y),dp[x][y]);
        dp[x][y] = max(lcs(x,y+1),dp[x][y]);
        if(s[0][x] == s[1][y]) dp[x][y] = max(lcs(x+1,y+1) + 1,dp[x][y]);
    }
    return dp[x][y];
}

int main() {
    int n;
    cin >> n;
    for(int i = 0;i < n;i++) {
        cin >> s[0] >> s[1];
        int res = -1;
        for(int j = 0;j < 1001 * 1001;j++)(reinterpret_cast<int*>(dp))[j] = -1;
        for(int j = 0;j < 1001 * 1001;j++)res = max(res,(reinterpret_cast<int*>(dp))[j]);
        cout << lcs(0,0) << endl;
    }
}

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

#define MAX 1000

int DP[MAX][MAX];

int main(){
  int n;
  
  std::cin >> n;
  
  for(int t = 0; t < n; t++){
    std::string str1, str2;

    std::cin >> str1;
    std::cin >> str2;
    
    const int one_len = str1.length();
    const int two_len = str2.length();
    
    for(int i = 0; i < one_len; i++){
      for(int j = 0; j < two_len; j++){
	DP[i][j] = 0;
      }
    }

    for(int i = 0; i < one_len; i++){
      for(int j = 0; j < two_len; j++){
	if(i == 0 && j == 0){
	  DP[i][j] = str1[i] == str2[j] ? 1 : 0;
	}else if(i == 0){	
	  DP[i][j] = std::max(DP[i][j-1], str1[i] == str2[j] ? 1 : 0);
	}else if(j == 0){
	  DP[i][j] = std::max(DP[i-1][j], str1[i] == str2[j] ? 1 : 0);
	}else{
	  DP[i][j] = std::max(DP[i-1][j-1] + (str1[i] == str2[j] ? 1 : 0), std::max(DP[i-1][j], DP[i][j-1]));
	}
      }
    }
    
    std::cout << DP[one_len - 1][two_len - 1] << std::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; // X[0]に空白を挿入
    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][j-1], C[i-1][j]);
            }
            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;
}