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(){
	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] = 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 <bits/stdc++.h>
using namespace std;
#define rep(i,n) for (int (i)=(0);(i)<(int)(n);++(i))
#define ALL(x) x.begin(),x.end()
typedef pair<int, int> P;
typedef long long ll;

int N;
string s,t;
int dp[1001][1001];

// int solve(int i, int j) {
//
//     if (dp[i][j] >= 0) {
//         return dp[i][j];
//     }
//
//     int res;
//     if (i >= n || j >= m) {
//         res = 0;
//     }
//     else if (s[i] == t[j]) {
//         res = solve(i+1, j+1) + 1;
//     }
//     else {
//         res = max(solve(i+1, j), solve(i, j+1));
//     }
//     return dp[i][j] = res;
// }

int main() {
    cin >> N;
    while (N--) {
        cin >> s >> t;
        int n = s.size(), m = t.size();
        fill(dp[0], dp[1001], 0);
        for (int i=0;i<n;++i) {
            for (int j=0;j<m;++j) {
                if (s[i] == t[j]) {
                    dp[i+1][j+1] = dp[i][j] + 1;
                }
                else {
                    dp[i+1][j+1] = max(dp[i+1][j], dp[i][j+1]);
                }
            }
        }
        cout << dp[n][m] << endl;
    }
}

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

int N,len1,len2;
string seq1,seq2;
int dp[1000][1000];

int main() {
	cin >> N;
	for (int M=0; M<N; M++){
		cin >> seq1 >> seq2;
		len1 = seq1.length();
		len2 = seq2.length();
		for (int i=1; i<=len1; i++){
			for (int j=1; j<=len2; j++){
				if (seq1[i-1] == seq2[j-1]){
					dp[i][j] = dp[i-1][j-1] + 1;
				}else if (dp[i][j-1] > dp[i-1][j]){
					dp[i][j] = dp[i][j-1];
				}else{
					dp[i][j] = dp[i-1][j];
				}
			}
		}
		cout << dp[len1][len2] << endl;
	}
	
	return 0;
}

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

using namespace std;

#if 0
http://judge.u-aizu.ac.jp/onlinejudge/review.jsp?rid=2065462#1
#endif

int n;
string a, b;
string x[10000], y[10000];




int main(){
  cin >> n;
  while(n != 0){
    n = n -1;
    int longest[1000][1000];
    cin >> a;
    cin >> b;
    a = ' ' + a;
    b = ' ' + b;
    int mm = 0;
    /*
    for(int i = 0; i < a.size(); ++i){
      for(int j = 0; j < b.size(); ++j){
        
        x[i] = a;
        y[j] = b;
      }
    }
    */
   //longest[0][0] =0;
   for(int i = 1; i <= a.size(); ++i){
     longest[i][0] = 0;
    }
   for(int j = 1; j <= b.size(); ++j){
     longest[0][j] = 0;
   }
    for(int i = 1; i <= a.size(); ++i){
      for(int j = 1; j <= b.size(); ++j){
        
        /*
        if(i <= 0 || j <=0){
          longest[i][j] = 0;
        }
        */
        if(a[i] == b[j]){
          longest[i][j] = 1 + longest[i-1][j - 1];
        }
        else{
          longest[i][j] = max(longest[i][j-1], longest[i-1][j]);
        }
        mm = max(mm, longest[i-1][j-1]);
      }
    }
    //cout << a[1] << endl;
    cout << mm << endl;
  }
}

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

using namespace std;

int main() {
    int Q = 0;
    string X,Y;
    cin>>Q;
    for (int q = 0; q < Q; q++) {
        cin>>X>>Y;

        int len[1001][1001] = {};
        for (int s = 1; s <= X.length(); s++) {
            for (int t = 1; t <= Y.length(); t++) {
                if (X[s] == Y[t]) len[s][t] = 1 + len[s-1][t-1];
                else len[s][t] = max(len[s-1][t], len[s][t-1]);
            }
        }
        cout<<len[X.length()][Y.length()]<<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.length();
	int n = Y.length();
	int maxlen = 0;
	X = ' ' + X;
	Y = ' ' + Y;
	for (int i = 0; i < m + 1; i++)c[i][0] = 0;
	for (int j = 1; j < n + 1; j++)c[0][j] = 0;

	for (int i = 1; i < m + 1; i++) {
		for (int j = 1; j < n + 1; 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]);
			}
			maxlen = max(maxlen, c[i][j]);
		}
	}
	return c[m][n];
}

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<iostream>
#include<iomanip>
#include<algorithm>
#include<bitset>
#include<cctype>
#include<climits>
#include<cmath>
#include<cstdio>
#include<cstring>
#include<deque>
#include<list>
#include<map>
#include<set>
#include<stack>
#include<string>
#include<sstream>
#include<queue>
#include<vector>
using namespace std;

//????????±?????¨??????
int lcs(string X, string Y) {
	static const int MAX_X = 1000, MAX_Y = 1000;
	static int dp[MAX_X + 1][MAX_Y + 1];
	memset(dp, 0, sizeof(dp));
	for (int i = 1; i <= X.size(); i++) {
		for (int j = 1; j <= Y.size(); j++) {
			if (X[i - 1] == Y[j - 1]) {
				dp[i][j] = dp[i - 1][j - 1] + 1;
			}
			else {
				dp[i][j] = max(
					dp[i - 1][j],
					dp[i][j - 1]
				);
			}
		}
	}
	return dp[X.size()][Y.size()];
}

int main() {
	int q; cin >> q;
	while (q--) {
		string X, Y; cin >> X >> Y;
		cout << lcs(X, Y) << endl;
	}
	return 0;
}

C++: #include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (int)(n); i++)
using namespace std;
using ll = long long;
using P = pair<int, int>;
template<class T> inline bool chmax(T &a, T b) { if (a<b) {a=b; return 1;} return 0;}
template<class T> inline bool chmin(T &a, T b) { if (b<a) {a=b; return 1;} return 0;}

int dp[1010][1010];

void solve() {
    string s, t;
    cin >> s >> t;
    memset(dp, 0, sizeof(dp));
    rep(i, s.size()) {
        rep(j, t.size()) {
            if (s[i] == t[j]) dp[i+1][j+1] = dp[i][j] + 1;
            else dp[i+1][j+1] = max(dp[i][j+1], dp[i+1][j]);
        }
    }
    cout << dp[s.size()][t.size()] << endl;
}

int main() {
    int q;
    cin >> q;
    rep(i, q) solve();
}