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++: #define _CRT_SECURE_NO_WARNINGS
#include <cstdio>
#include <cstdlib>
#include <string>
#include <iostream>
#include <queue>

using namespace std;

const char *X, *Y;
int X_length, Y_length;

int table_lcs[1001][1001];

int lcs(int x_begin, int y_begin) {
	int i, j, to;
	int max = 0;
	int v_lcs;
	bool alreadySeenTable[256];
	if (table_lcs[x_begin][y_begin] != -1) {
		return table_lcs[x_begin][y_begin];
	}
	
	for (i = 0; i < 256; i++) {
		alreadySeenTable[i] = false;
	}
	i = x_begin;
	to = Y_length-1;
	while(i <= X_length-1) {
		j = y_begin;
		if (alreadySeenTable[X[i]] == true) {
			i++;
			continue;
		}
		bool found = false;
		while (j <= to) {
			if (X[i] == Y[j]) {
				v_lcs = lcs(i + 1, j + 1) + 1;
				if (v_lcs > max) {
					max = v_lcs;
				}
				found = true;
				break;
			}
			else {
				j++;
			}
		}
		if (found == false) {
			alreadySeenTable[X[i]] = true;
			i++;
		}
		else {
			alreadySeenTable[X[i]] = true;
			i++;
			to = j - 1;
		}
	}
	return table_lcs[x_begin][y_begin] = max;
}

int main() {

	int N;
	cin >> N;
	string stringX, stringY;

	for (int i = 1; i <= N; i++) {
		for (int i = 0; i < 1001; i++) {
			for (int j = 0; j < 1001; j++) {
				table_lcs[i][j] = -1;
			}
		}
		cin >> stringX >> stringY;
		X = stringX.c_str();
		X_length = stringX.size();
		Y = stringY.c_str();
		Y_length = stringY.size();
		printf("%d\n", lcs(0, 0));
	}
	return 0;
}

C++: #include <bits/stdc++.h>
#define _GLIBCXX_DEBUG
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rrep(i, n) for (int i = 1; i < (n+1); ++i)
using namespace std;
using ll = long long;
// const int INF = +100100100;
// typedef pair<int,int> P;

// int dp(int i, int j, string x, string y, char D[MAX][MAX]){
//     if(x[i-1]==y[j-1])return D[i-1][j-1]+1;
//     else{
//         return max(D[i-1][j],D[i][j-1]);
//     }
// }

int lcs(string x, string y){
    int D[x.size()+1][y.size()+1];
    rep(i,x.size()+1)D[i][0]=0;
    rep(i,y.size()+1)D[0][i]=0;
    rrep(i,x.length()){
        rrep(j,y.length()){
            if(x[i-1]==y[j-1])D[i][j]= D[i-1][j-1]+1;
            else{
                D[i][j]= max(D[i-1][j],D[i][j-1]);
            }
        }
    }
    int ans = D[x.length()][y.length()];
    return ans;
}

int main(){
    int n;cin>>n;
    rep(i,n){
        string x,y;
        cin >> x >> y;
        printf("%d\n",lcs(x,y));
    }
    return 0;
}

C++: #include<iostream>
#include<string>
#include<algorithm>
#include<map>
#include<vector>
using namespace std;
map <char,vector<int>> alx,aly;//x,y
int memo[1010][1010];
string x,y,q;
int lcs(int xn,int yn){//yn文字目以降でX[xn]と同じやつを探す
    if(memo[xn][yn]!=-1)return memo[xn][yn];
    int ans=0;
	/*
    for(int i=xn; i<x.size();i++){
        for(int j=yn; j<y.size(); j++){
            if(alx[x[i]]==aly[y[j]]){
                ans=max(ans,lcs(i+1,j+1)+1);
            }
        }
    }
	*/
	for(int i=xn; i<x.size();i++){
        for(int j=0; j<aly[x[i]].size(); j++){
			if(aly[x[i]][j] < yn) continue;
			ans=max(ans,lcs(i+1,aly[x[i]][j]+1)+1);
		}
    }
    return memo[xn][yn]=ans;
}
 
 
int main(){
    int q;
    cin >> q;
    for(int ds=0; ds<q; ds++){
 
        cin >> x >> y;
        for(int i=0; i<=x.size(); i++){
            for(int j=0; j<=y.size(); j++){
				memo[i][j]=-1;
			}
        }

		for(int i=0; i<x.size(); i++) alx[x[i]].push_back(i);
		for(int i=0; i<y.size(); i++) aly[y[i]].push_back(i);
		

        //memset(memo, -1, sizeof(memo));
         
        cout << lcs(0,0) << endl;
 
    }
    return 0;
}

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

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

string str1, str2;
int dp[1001][1001];

void solve()
{
  REP(i, str1.size())
    if(str1[i] == str2[str2.size() - 1])
      dp[i][str2.size() - 1] = 1;
    else
      dp[i][str2.size() - 1] = 0;
  for(int i = str2.size() - 2; i >= 0; i--)
    if(str1[str1.size() - 1] == str2[i])
      dp[str1.size() - 1][i] = 1;
    else
      dp[str1.size() - 1][i] = dp[str1.size() - 1][i + 1];
  for(int i = str1.size() - 2; i >= 0; i--){
    for(int j = str2.size() - 2; j >= 0; j--){
      if(str1[i] == str2[j])
	dp[i][j] = dp[i + 1][j + 1] + 1;
      else
	dp[i][j] = max(dp[i + 1][j], dp[i][j + 1]);
    }
  }
}
  
int main()
{
  int q;
  cin >> q;
  cin.ignore();
  REP(i, q){
    getline(cin, str1);
    getline(cin, str2);
    if(str1.size() < str2.size())
      swap(str1, str2);
    fill(&dp[0][0], &dp[1001][0], -1);
    solve();
    cout << dp[0][0] << endl;
  }
}

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

#define MAX_N 1000
#define MAX_M 1000

void solve();

string s, t;
int dp[MAX_N + 1][MAX_M + 1];

void solve(){
	for(int i = 0; i < s.length(); i++){
		for(int j = 0; j < t.length(); j++){
			if(s[i] == t[j]){
				dp[i + 1][j + 1];
					dp[i + 1][j + 1] = dp[i][j] + 1;
				} else {
					dp[i + 1][j + 1] = max(dp[i][j], dp[i + 1][j]);
				}
			}
		}
		cout << dp[s.length()][t.length()] << endl;
}

int main(){
	int n;
	cin >> n;
	for(int i = 0; i < n; i++){
		cin >> s >> t;
		solve();
	}
	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 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 q;
  cin >> q;

  for ( int i = 0; i < q; i++ ) {
    cin >> s1 >> s2;
    cout << lcs(s1, s2) << endl;
  }

  return 0;
}