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<iostream>
#include<algorithm>
#include<vector>
#include<string>

const int s=1000;

using namespace std;

int main(){
	ios::sync_with_stdio(false);
	cin.tie(0);

	int q;
	string X,Y;
	static unsigned int dp[s][s] = {0};
	
	dp[0][0] = 0; dp[0][1] = 0; dp[1][0] = 0;

	cin >> q;
	for(int k=0; k < q; k++){
		cin >> X >> Y;
		int i,j;
		for(i=0;i<X.size();i++){
			for(j=0;j<Y.size();j++){
				if(X[i] == Y[j]) dp[i+1][j+1] = dp[i][j] + 1;
				else dp[i+1][j+1] = max(dp[i][j+1],dp[i+1][j]);
			}
		}
		cout << dp[i][j] << "\n";
	}
	return 0;
}

C++: #include <bits/stdc++.h>
#define MAX 1000
using namespace std;
int lcs(string,string);

int main(){
  int i,n;
  string st1,st2;

  cin >> n;
  for(i = 0; i < n; i++){
    cin >> st1 >> st2;
    cout << lcs(st1,st2) << endl;
  }
  return 0;
}

int lcs(string st1,string st2){
  int preMax = 0;
  int m,n,i,j;
  int key[MAX+1][MAX+1];

  m = st1.size();
  n = st2.size();
  /**/
  st1 = ' '+st1;
  st2 = ' '+st2;
  for(i = 1; i <= m; i++){
    key[i][0] = 0;
  }
  for(j = 1; j <= n; j++){
    key[0][j] = 0;
  }
  for(i = 1; i <= m; i++){
    for(j = 1; j <= n; j++){
      if(st1[i] == st2[j]){
        key[i][j] = key[i-1][j-1]+1;
      }
      else{
        key[i][j] = max(key[i-1][j],key[i][j-1]);
      }
      preMax = max(preMax,key[i][j]);
    }
  }
  return preMax;
}

C++: #include<stdio.h>
#include<string.h>
????????
int LCS(char *X, char *Y){
????int i,j,m,n,c[1001][1001];
????m = strlen(X);
????n = strlen(Y);
????????????
????for(i=0; i<m; i++){
????????c[i][0] = 0;
????}
????for(j=0; j<n; j++){
????????c[0][j] = 0;
????}
????????
????for(i=1;i<m+1;i++){
????????for(j=1;j<n+1;j++){
????????????if (X[i-1]==Y[j-1]) c[i][j]=c[i-1][j-1]+1;
????????????else if (c[i-1][j]>=c[i][j-1]) c[i][j]=c[i-1][j];
????????????else c[i][j]=c[i][j-1];
????????}
????}
????return c[i-1][j-1];
}
????????
int main(){
????int i, q;
????char X[1001], Y[1001];
????????????
????scanf("%d", &q);
????for(i=0; i<q; i++){
????????scanf("%s", X);
????????scanf("%s", Y);
????????printf("%d\n", LCS(X, Y));
????????
????}
????return 0;
}

C++: #include<stdio.h>
#include<string>
#include<algorithm>
using namespase 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 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>

#define M_PI       3.14159265358979323846   // pi

using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef vector<ll> VI;
typedef pair<ll, ll> P;
typedef tuple<ll, ll, ll> t3;
typedef tuple<ll, ll, ll, ll> t4;
typedef tuple<ll, ll, ll, ll, ll> t5;

#define rep(a,n) for(ll a = 0;a < n;a++)
#define repi(a,b,n) for(ll a = b;a < n;a++)

using namespace std;

static const ll INF = 1e15;

struct LongestCommonSubsequence {
    static const int max_length = 1001;
    std::vector<std::vector<int>> dp;
    std::vector<std::vector<int>> pre;
    std::string s, t;

    LongestCommonSubsequence(std::string left, std::string right) {
        s = "+" + left;
        t = "*" + right;
        dp.assign(max_length, std::vector<int>(max_length, 0));
        pre.assign(max_length, std::vector<int>(max_length, 0));
    }

    void lcs() {

        for (int si = 1; si < s.size(); si++) {
            for (int ti = 1; ti < t.size(); ti++) {
                if (s[si] == t[ti]) {
                    dp[si][ti] = dp[si - 1][ti - 1] + 1;
                    pre[si][ti] = 1;
                }
                else if (dp[si - 1][ti] > dp[si][ti - 1]) {
                    dp[si][ti] = dp[si - 1][ti];
                    pre[si][ti] = 2;
                }
                else {
                    dp[si][ti] = dp[si][ti - 1];
                    pre[si][ti] = 3;
                }
            }
        }
    }

    std::string solve() {
        std::string ans = "";

        int si = s.size() - 1;
        int ti = t.size() - 1;
        while (si >= 1 && ti >= 1) {
            if (pre[si][ti] == 1) {
                ans += s[si];
                si--, ti--;
            }
            else if (pre[si][ti] == 2) {
                si--;
            }
            else {
                ti--;
            }
        }

        reverse(ans.begin(), ans.end());
        return ans;
    }
};

int main() {
    ll q;
    cin >> q;
    rep(i, q) {
        string s, t;
        cin >> s >> t;
        LongestCommonSubsequence seq(s, t);
        seq.lcs();
        cout << seq.solve().size() << endl;
    }
    return 0;
}

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

int main(){

  int n;
  int dp[1111][1111];

  cin >> n;
  while(n--){
    string str1, str2;
    cin >> str1 >> str2;

    memset(dp,0,sizeof(dp));

    for(int i = 1; i <= str1.size(); i++){
      for(int j = 1; j <= str2.size(); 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]);
      }
    }
    cout << dp[str1.size()][str2.size()] << endl;

  }
}