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++: #include<bits/stdc++.h>
#include<iostream>
#include<cstdio>
#include<vector>
#include<string>
#include<algorithm>
using namespace std;
#define rep(i,x) for(int i = 0; i < x; i++)
#define pb(x) push_back(x)
#define mp(x,y) make_pair(x,y)
typedef long long ll;
typedef pair<int,int> P;
typedef vector<int> ivec;
const ll N = 1e9+7;

int main(){
    int q; cin >> q;
    string x[q],y[q];
    rep(i,q){
        cin >> x[i] >> y[i];
    }
    int ans[q];
    rep(i,q){
        int dp[1010][1010] = {};
        int xlen = x[i].size();
        int ylen = y[i].size();
        // cout << x[i] << ' ' << xlen << ' ' << y[i] << ' ' << ylen << endl;
        dp[0][0] = 0;
        rep(j,xlen+1){
            if(!j)continue;
            rep(k,ylen+1){
                if(!k)continue;
                if(x[i][j-1] == y[i][k-1]) {
                    dp[j][k] = dp[j-1][k-1] + 1;
                    // cout << i  << ' ' << j  << ' ' << k << ' ' <<  dp[j][k] << endl;
                }
                else{
                    dp[j][k] = max(dp[j-1][k],max(dp[j][k-1],dp[j-1][k-1]));
                }
            }
        }
        ans[i] = dp[xlen][ylen];
    }

    rep(i,q) cout << ans[i] << endl;
    return 0;
}

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

#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)

static const int N = 10000;

int lcs(string X, string Y);

int main(void){
	string s1, s2;
	int n; cin >> n;
	int i;
	REP(i, n) {
		cin >> s1 >> s2;
		cout << lcs(s1, s2) << endl;
	}
	return 0;
}

// longest common sequence
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;
	int i, j;
	FOR(i, 1, m + 1) FOR(j, 1, n + 1) {
		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;
}

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

using namespace std;

#define N 1000

int LCS(string x, string y){
  int apx[N+1][N+1];
  int a=x.size();
  int k=y.size();
  int max_l =0;

  x=' '+x;
  y=' '+y;

  for(int i=0;i<=a;i++) apx[i][0] =0;
  for(int j=0;j<=k;j++) apx[0][j] =0;

  for(int i=1;i<=a;i++){
    for(int j=1;j<=k;j++){
      if(x[i] == y[j])  apx[i][j] = apx[i-1][j-1] +1;
      else apx[i][j] = max(apx[i-1][j],apx[i][j-1]);
      max_l=max(max_l,apx[i][j]);
    }
  }
  return max_l;
}


int main(){
  int q;
  string x,y;

  cin >> q;

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


}

C++: #include <iostream>
#include <set>
#include <math.h>
#include <list>
#include <vector>
#include <map>
#include <algorithm>
using namespace std;
#define rep(i, n) for (int i = 0; i < n; i++)
#define MAX_N 1005
#define MAX_M 100

long long A[MAX_N];
long long B[MAX_N];
int MOD = 1000000000 + 7;
string S;

int dp[MAX_N][MAX_N];
int lcs(string S, string T)
{
    rep(i, S.length())
    {
        rep(j, T.length())
        {
            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]);
            }
        }
    }
    return dp[S.length()][T.length()];
}

int main()
{
    rep(i, MAX_N)
    {
        dp[i][0] = 0;
        dp[0][i] = 0;
    }
    int Q;
    cin >> Q;
    string S, T;
    rep(i, Q)
    {
        cin >> S >> T;
        cout << lcs(S, T) << 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 = 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 << lcs(s1, s2) << endl;
  }
  return 0;
}

C++: #include <iostream>
#include <algorithm>
#include <string>
#include <vector>
#include <list>
#include <queue>
#include <stack>
#include <set>
#include <cmath>
#include <cstring>

#define LP(i,n) for(int i=0;i<n;i++)
#define Mset(x,v) memset(x,v,sizeof(x))

using namespace std;
using LL=long long;

int main(){
    int n,x,y,maxl;
    string X,Y;
    cin>>n;
    LP(i,n){
        int c[1001][1001];
        cin>>X>>Y;
        x=X.size();
        y=Y.size();
        X=' '+X;
        Y=' '+Y;
        maxl=0;
        for(int j=0;j<=x;j++) c[j][0]=0;
        for(int j=1;j<=y;j++) c[0][j]=0;
        for(int j=1;j<=x; j++){
            for(int k=1;k<=y;k++){
                if(X[j]==Y[k]){
                    c[j][k]=c[j-1][k-1]+1;
                }
                else{
                    c[j][k]=max(c[j-1][k],c[j][k-1]);
                }
                maxl=max(maxl,c[j][k]);
            }
        }
        cout<<maxl<<endl;
    }
    return 0;
}