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++: // Last Change: 12/29/2018 23:21:03.
//
// XとYの先頭に空白を入れることで、探索するべき要素のindexを0~m-1ではなく
// 1~mにしている。これにより、一番最初のcの更新において、i=j=0におけるc[i-1][j-1]
//すなわちc[-1][-1]にアクセスしてしまうことを防いでいる。
//
//***********************************************************************
//下から順番に計算していく方法
//
//***********************************************************************

#include <algorithm>
#include <array>
#include <bitset>
#include <cmath>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <vector>

using namespace std;
using ll = long long;

#define MAXLENGTH 1001

int LCS(string, string);

int LCS(string X, string Y) {
  static int c[MAXLENGTH][MAXLENGTH];
  for (int i = 0; i < MAXLENGTH; i++) {
    c[i][0] = c[0][i] = 0;
  }
  int m, n, maxL;
  m = X.size();
  n = Y.size();
  maxL = 0;
  X = ' ' + X;
  Y = ' ' + Y;
  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() {
  int q;
  cin >> q;
  string X, Y;
  for (int i = 0; i < q; i++) {
    cin >> X >> Y;
    cout << LCS(X, Y) << endl;
  }
}

C++: #include <iostream>
#include <string>
#include <algorithm>
const int MAX_S = 1005;
using namespace std;

int main(void) {
    int q;
    cin >> q;
    for (int i = 0; i < q; i++) {
        string x, y;
        cin >> x >> y;
        x = ' ' + x;
        y = ' ' + y;

        int dp[MAX_S][MAX_S];
        for (auto j = 1; j < x.size(); j++) {
            dp[j][0] = 0;
        }
        for (auto k = 1; k < y.size(); k++) {
            dp[0][k] = 0;
        }

        int maxlength = 0;
        for (auto j = 1; j < x.size(); j++) {
            for (auto k = 1; k < y.size(); k++) {
                if (x[j] == y[k]) {
                    dp[j][k] = dp[j-1][k-1] + 1;
                } else {
                    dp[j][k] = max(dp[j-1][k], dp[j][k-1]);
                }
                maxlength = max(maxlength, dp[j][k]);
            }
        }

        cout << maxlength << endl;
    }

    return 0;
}

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

using namespace std;

static const int N = 100;

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; // X[0]?????????????????\
  Y = ' ' + Y; // Y[0]?????????????????\
  for (int i = 1; i <= m; i++) {
    for (int j = 1; j <= n; j++) {
      if (X[i] == Y[i]) {
        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 <string>
#include <vector>

int main(int argc, char const *argv[]) {
  int q;
  std::cin >> q;
  for (size_t _ = 0; _ < q; _++) {
    std::string x, y;
    std::cin >> x;
    std::cin >> y;

    std::vector<std::vector<int> > dp(x.size()+1, std::vector<int>(y.size()+1));
    for (size_t ii=0; ii<x.size(); ++ii){
      for(size_t jj=0; jj<y.size(); ++jj){
        size_t i = ii + 1;
        size_t j = jj + 1;
        if (x[ii]==y[jj]){
          dp[i][j] = dp[i-1][j-1] + 1;
        }
        else{
          dp[i][j] = std::max(dp[i-1][j], dp[i][j-1]);
        }
      }
    }
    std::cout << dp[x.size()][y.size()] << std::endl;
  }
  return 0;
}

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

int lcs(string str1, string str2)
{
	int len[1001][1001] = { 0 };

	int len1 = str1.size();
	int len2 = str2.size();
	str1 = ' ' + str1;
	str2 = ' ' + str2;

	for (int i = 0; i <= len1; i++)
		for (int j = 0; j <= len2; j++) len[i][j] = 0;

	for (int i = 1; i <= len1; i++)
	{
		for (int j = 1; j <= len2; j++)
		{
			if (str1[i] == str2[j]) len[i][j] = len[i - 1][j - 1] + 1;
			else len[i][j] = max(len[i - 1][j], len[i][j - 1]);
		}
	}
	return len[len1][len2];
}

int main()
{
	int n;
	string str1, str2;

	cin >> n;
	for (int i = 0; i < n; i++)
	{
		cin >> str1 >> str2;
		cout << lcs(str1, str2) << endl;
	}

	return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;

int solve(string x, string y){
    int m = x.length();
    int n = y.length();
    int maxl = 0;
    int c[1001][1001];
    
    for(int i = 0; i < m; i++) c[i][0] = 0;
    for(int i = 0; i < n; i++) c[0][i] = 0;
    x = ' ' + x;
    y = ' ' + y;

    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]);
            }
            maxl = max(maxl,c[i][j]);
        }
    }
    return maxl;
}

int main(){
    int q, l = 0;
    string x,y;
    vector<int> a;

    cin >> q;
    for(int i = 0; i < q; i++){
        cin >> x >> y;
        a.push_back(solve(x,y));
    }

    for(auto i: a){
        cout << i << 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;
}