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 <cstring>

using namespace std;

int main(void)
{
    int q;
    char x[1001], y[1001];
    int table[1001][1001];
    
    cin >> q;
    for (int i = 0; i < q; i++) {
	cin >> x >> y;
	int xl = strlen(x), yl = strlen(y);

	for (int i = 0; i < xl; i++)
	    table[i][0] = x[i] == y[0];
	for (int j = 0; j < yl; j++)
	    table[0][j] = x[0] == y[j];

	for (int i = 1; i < xl; i++)
	    for (int j = 1; j < yl; j++)
		if (x[i] == y[j])
		    table[i][j] = 1 + table[i-1][j-1];
		else
		    table[i][j] = max(table[i-1][j], table[i][j-1]);

	cout << table[xl - 1][yl - 1] << endl;
    }

    return 0;
}

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

string S,T;
int x[10000],y[10000];
int dp[10000][10000];
char U[5]="abcd";
int MAXN;

int main(){
	int q;
	cin>>q;
	for(int i=0;i<q;i++){
		MAXN=0;
		cin>>S>>T;
		for(int i=0;i<S.size();i++){
			for(int j=0;j<4;j++){
				if(S[i]==U[j]){
					x[i+1]=j;
				}
			}
		}
		for(int i=0;i<T.size();i++){
			for(int j=0;j<4;j++){
				if(T[i]==U[j]){
					y[i+1]=j;
				}
			}
		}
		for(int i=0;i<=T.size();i++){
			for(int j=0;j<=S.size();j++){
				if(i==0 || j==0){
					dp[i][j]=0;
				}
				else if(x[j]==y[i]){
					dp[i][j]=dp[i-1][j-1]+1;
				}
				else{
					dp[i][j]=max(dp[i][j-1],dp[i-1][j]);
				}
			}
		}
		for(int i=0;i<=T.size();i++){
			for(int j=0;j<=S.size();j++){
				MAXN=max(MAXN,dp[i][j]);
			}
		}
		cout<<MAXN<<endl;
	}
	return 0;
}

C++: #include <cstdio>
#include <cmath>
#define MAX 1001
using namespace std;

int Lcc(const char *X, const char *Y) {
    int lcc = 0;
    int dp[MAX][MAX];
    for (int i=0; i<MAX; i++)
        for (int j=0; j<MAX; j++) dp[i][j] = 0;

    int x=0, y=0;
    for (int i=0;;i++) {
        if (X[i] == ',') {x = i;break;}
        for (int j=0;;j++) {
            if (Y[j] == ',') {
                y = j;
                break;
            } else {
                if (X[i] == Y[j]) {
                    dp[i+1][j+1] = fmax(dp[i][j] + 1, dp[i+1][j]);
                } else {
                    dp[i+1][j+1] = fmax(dp[i+1][j], dp[i][j+1]);
                }
            }
        }
    }
    return dp[x-1][y-1];
}

int
main()
{
    int q;
    scanf("%d", &q);
    for (int i=0; i<(q); i++) {
        char X[MAX], Y[MAX];
        for (int i=0; i<MAX; i++) {
            X[i] = ','; Y[i] = ',';
        }
        scanf(" %s", X);scanf(" %s", Y);
        int LCC = Lcc(X, Y);
        printf("%d\n", LCC);
    }
    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;
  c[0][0] = 0;
  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]);
    }
  }javascript:void(0)

  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;
}