Go: package main

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

// I/O
type Scanner struct {
	sc *bufio.Scanner
}

func NewScanner() *Scanner {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Buffer(make([]byte, 1024), int(1e+9))
	return &Scanner{sc}
}

func (s *Scanner) nextStr() string {
	s.sc.Scan()
	return s.sc.Text()
}

func (s *Scanner) nextInt() int {
	i, e := strconv.Atoi(s.nextStr())
	if e != nil {
		panic(e)
	}
	return i
}

func (s *Scanner) nextFloat() float64 {
	f, e := strconv.ParseFloat(s.nextStr(), 64)
	if e != nil {
		panic(e)
	}
	return f
}

func (s *Scanner) nextRuneSlice() []rune {
	return []rune(s.nextStr())
}

func (s *Scanner) nextIntSlice(n int) []int {
	res := make([]int, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextInt()
	}
	return res
}

func (s *Scanner) nextFloatSlice(n int) []float64 {
	res := make([]float64, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextFloat()
	}
	return res
}

// Arithmetic
func max(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m < i {
			m = i
		}
	}
	return m
}

func min(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m > i {
			m = i
		}
	}
	return m
}

func abs(x int) int {
	if x > 0 {
		return x
	}
	return -x
}

func pow(x, y int) int {
	res := 1
	for i := 0; i < y; i++ {
		res *= x
	}
	return res
}

func ceil(a, b int) int {
	if a%b == 0 {
		return a / b
	} else {
		return a/b + 1
	}
}

// Sort
type RuneSlice []rune

func (a RuneSlice) Len() int           { return len(a) }
func (a RuneSlice) Less(i, j int) bool { return a[i] < a[j] }
func (a RuneSlice) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }

// Main
func main() {
	sc := NewScanner()
	wtr := bufio.NewWriter(os.Stdout)
	Q := sc.nextInt()
	for q := 0; q < Q; q++ {
		X, Y := sc.nextStr(), sc.nextStr()
		xLen, yLen := len(X), len(Y)
		dp := make([][]int, xLen+1)
		for i := 0; i <= xLen; i++ {
			dp[i] = make([]int, yLen+1)
		}
		for x := 0; x <= xLen; x++ {
			for y := 0; y <= yLen; y++ {
				if x == 0 || y == 0 {
					dp[x][y] = 0
				} else if X[x-1] == Y[y-1] {
					dp[x][y] = dp[x-1][y-1] + 1
				} else {
					dp[x][y] = max(dp[x-1][y], dp[x][y-1])
				}
			}
		}
		fmt.Fprintln(wtr, dp[xLen][yLen])
	}

	wtr.Flush()
}

C++: #include <bits/stdc++.h>
using namespace std;
typedef long long lint;
#define FOR(i, o, n) for (auto i = (o); (i) < (n); ++(i))
#define REP(i, n) FOR(i, 0, n)
#define REPR(i, n) for (auto i = (n)-1; (i) >= 0; --i)
#define REPI(itr, v) for (auto itr = v.begin(); itr != v.end(); ++itr)
#define REPIR(itr, v) for (auto itr = v.rbegin(); itr != v.rend(); ++itr)
#define fi first
#define se second
#define ll long long
#define V2(name, h, w) vector<vector<int> > name((h), vector<int>(w));
int lcs(string X, string Y)
{
	int m = X.size(), n = Y.size();
	X = ' ' + X, Y = ' ' + Y;
	V2(C, 1001, 1001);
	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]);
			}
		}
	}
	return C[m][n];
}
int main(){
	int q; cin >> q;
	REP(i, q){
		string X, Y;
		cin >> X >> Y;
		cout << lcs(X, Y) << endl; 
	}
}

C++: #include <vector>
#include <iostream>
#include <string>
#include <algorithm>
#include <iterator>
using namespace std;
int main(){
	int n;
	cin >> n;
	while(n--){
		string a,b;
		cin >> a >> b;
		int asize = a.size(),bsize = b.size();
		vector<vector<int> > dp(asize+1,vector<int>(bsize+1,0));
		for(int i=1;i<asize+1;i++){
			for(int j=1;j<bsize+1;j++){
				if(a[i-1] == b[j-1]){
					dp[i][j] = dp[i-1][j-1] + 1;
				}else{
					dp[i][j] = max(dp[i-1][j],dp[i][j-1]);
				}
			}
		}
		/*				for(int i = 0;i<asize+1;i++){
		copy(dp[i].cbegin(),dp[i].cend(),ostream_iterator<int>(cout, " ") );
		cout << endl;
		}*/
				
		cout << dp[asize][bsize] << endl;
	}
}

C++: #include <cstdio>
#include <cstring>
#include <algorithm>
#include <cstdlib>
#include <vector>
using namespace std;

#define max(a, b) ((a) > (b) ? (a) : (b))

const int MAX_N = 1010;
int dp[MAX_N][MAX_N];

int solve(char str1[], char str2[]) {
    memset(dp, 0, sizeof(dp));
    int sz1 = strlen(str1);
    int sz2 = strlen(str2);
    for(int i = 1; i <= sz1; ++i) {
        for(int j = 1; j <= sz2; ++j) {
            if(str1[i - 1] == str2[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[sz1][sz2];
}

int main() {
    int t;
    char str1[MAX_N];
    char str2[MAX_N];
    scanf("%d\n", &t);
    while(t--) {
        gets(str1);
        gets(str2);
        printf("%d\n", solve(str1, str2));  
    }
    return 0;
}

C++: //
// Created by ?????°?????? on 2016/04/21.
//

#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 = 0; 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;

long lcs(string x, string y) {
    long m = x.size();
    long n = y.size();
    x = ' ' + x;
    y = ' ' + y;
    long dp[m + 1][n + 1];
    for (long i = 0; i <= m; i++) {
        dp[i][0] = 0;
    }
    for (long i = 0; i <= n; i++) {
        dp[0][i] = 0;
    }

    long lcs_max = 0;
    for (long i = 1; i <= m; i++) {
        for (long j = 1; j <= n; j++) {
            if (x[i] == y[j]) {
                dp[i][j] = dp[i - 1][j - 1] + 1;
            }
            else {
                dp[i][j] = max(dp[i - 1][j], dp[i][j - 1]);
            }
            lcs_max = max(lcs_max, dp[i][j]);
        }
    }
    return lcs_max;
}

int main() {
    long q;
    string x, y;
    cin >> q;
    for (long i = 0; i < q; i++) {
        cin >> x >> y;
        cout << lcs(x, y) << endl;
    }
    return 0;
}

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

int q;
string X,Y;
int L[1000][1000];

int max(int i,int j) {return i > j ? i : j;}

int getL(int i,int j) {
	if(L[i][j] != -1) return L[i][j];

	if(i == 0 || j == 0) return 0;
	if(X[i - 1] == Y[j - 1]) return 1 + getL(i - 1,j - 1);
	return max(getL(i,j - 1),getL(i - 1,j));
}

int main() {

	cin >> q;
	for(int i = 0;i < q;i++) {
		for(int j = 0;j < 1000;j++) {
			for(int k = 0;k < 1000;k++) L[j][k] = -1;
		}
		cin >> X >> Y;
		cout << getL(X.size(),Y.size()) << endl;
	}
}

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

using namespace std;

int q;
int main() {
	cin >> q;
	for (int i = 0; i < q; i++) {
		string x, y;
		cin >> x >> y;
		int m = x.size();
		int n = y.size();
		x = ' ' + x;
		y = ' ' + y;
		int maxl = 0;
		int c[1001][1001] = {};
		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]);
				}
			}
		}
		cout << c[m][n] << endl;
	}
	return 0;
}