Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

var sc = bufio.NewScanner(os.Stdin)

func scanInt() int {
	num, _ := strconv.Atoi(scanString())
	return num
}

func scanString() string {
	sc.Scan()
	return sc.Text()
}

func init() {
	sc.Split(bufio.ScanWords)
}

func max(a, b int) int {
	if a > b {
		return a
	}
	return b
}

func lcs(a, b string) int {
	lenA := len(a)
	lenB := len(b)
	dp := make([][]int, lenA+1)
	for i := range dp {
		dp[i] = make([]int, lenB+1)
	}

	for i := 1; i <= lenA; i++ {
		for j := 1; j <= lenB; j++ {
			if a[i-1] == b[j-1] {
				dp[i][j] = dp[i-1][j-1] + 1
			} else {
				dp[i][j] = max(dp[i][j-1], dp[i-1][j])
			}
		}
	}
	return dp[lenA][lenB]
}

func main() {
	n := scanInt()
	w := bufio.NewWriter(os.Stdout)
	for i := 0; i < n; i++ {
		a := scanString()
		b := scanString()
		fmt.Fprintln(w, lcs(a, b))
	}
	w.Flush()
}

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.length();
	int n = Y.length();
	int maxlen = 0;
	X = ' ' + X;
	Y = ' ' + Y;
	for (int i = 0; i < m + 1; i++)c[i][0] = 0;
	for (int j = 1; j < n + 1; j++)c[0][j] = 0;

	for (int i = 1; i < m + 1; i++) {
		for (int j = 1; j < n + 1; 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]);
			}
			maxlen = max(maxlen, c[i][j]);
		}
	}
	return c[m][n];
}

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;
}

C++: #include<iostream>
#include<iomanip>
#include<algorithm>
#include<bitset>
#include<cctype>
#include<climits>
#include<cmath>
#include<cstdio>
#include<cstring>
#include<deque>
#include<list>
#include<map>
#include<set>
#include<stack>
#include<string>
#include<sstream>
#include<queue>
#include<vector>
using namespace std;

//????????±?????¨??????
int lcs(string X, string Y) {
	static const int MAX_X = 1000, MAX_Y = 1000;
	static int dp[MAX_X + 1][MAX_Y + 1];
	memset(dp, 0, sizeof(dp));
	for (int i = 1; i <= X.size(); i++) {
		for (int j = 1; j <= Y.size(); j++) {
			if (X[i - 1] == Y[j - 1]) {
				dp[i][j] = dp[i - 1][j - 1] + 1;
			}
			else {
				dp[i][j] = max(
					dp[i - 1][j],
					dp[i][j - 1]
				);
			}
		}
	}
	return dp[X.size()][Y.size()];
}

int main() {
	int q; cin >> q;
	while (q--) {
		string X, Y; cin >> X >> Y;
		cout << lcs(X, Y) << endl;
	}
	return 0;
}

C++: #include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (int)(n); i++)
using namespace std;
using ll = long long;
using P = pair<int, int>;
template<class T> inline bool chmax(T &a, T b) { if (a<b) {a=b; return 1;} return 0;}
template<class T> inline bool chmin(T &a, T b) { if (b<a) {a=b; return 1;} return 0;}

int dp[1010][1010];

void solve() {
    string s, t;
    cin >> s >> t;
    memset(dp, 0, sizeof(dp));
    rep(i, s.size()) {
        rep(j, t.size()) {
            if (s[i] == t[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[s.size()][t.size()] << endl;
}

int main() {
    int q;
    cin >> q;
    rep(i, q) solve();
}

C++: #include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cassert>
#include <string>
#include <cstring>
#include <vector>
#include <list>
#include <map>
#include <set>
#include <stack>
#include <queue>
#include <algorithm>

using namespace std;

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

// debug
#define dump(x)  cerr << #x << " = " << (x) << endl;
#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl;

// ---------------------
#define INF 922337203685477580
typedef long long ll;

int dp[1000][1000];

int main() {
  int q;
  cin >> q;
  REP(loop, q) {
    char S[1000], T[1000];
    cin >> S >> T;

    FOR(i, strlen(S)) {
      FOR(j, strlen(T)) {
        dp[i][j] = 0;
      }
    }
    for (int i = 0; i < strlen(S); i++) {
      for (int j = 0; j < strlen(T); j++) {
        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]);
        }
      }
    }
    cout << dp[strlen(S) - 1][strlen(T) - 1] << endl;
  }

  return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
int C[1000][1000];
int lc(string F, string S){
    fill(C[0],C[1000],0);
    int m = F.size(), n = S.size();
    int len=0;
    for(int i=0; i<m; i++){
        for (int j = 0; j < n; ++j) {
            if (F[i] == S[j]) {
                if (i - 1 >= 0 && j - 1 >= 0)
                    C[i][j] = C[i - 1][j - 1] + 1;
                else
                    C[i][j] = 1;
            } else if (i - 1 >= 0 && j - 1 >= 0) {
                C[i][j] = max(C[i-1][j], C[i][j - 1]);
            }
            len = max(len, C[i][j]);
        }
    }
    return len;
}

int main() {
    ios::sync_with_stdio(false);
    int n;
    cin >> n;
    string ar[n*2];
    for (int i = 0; i < n * 2; ++i) {
        cin >> ar[i];
    }
    for (int j = 0; j < n*2; j+=2) {
        cout << lc(ar[j],ar[j+1]) << endl;
    }
    return 0;
}

C++: // Ref : https://book.mynavi.jp/ec/products/detail/id=35408

#include <iostream>
#include <algorithm>
#include <limits.h>
using namespace std;

static const int N = 100;;

int main() {
	int n; cin >> n;
	int p[N + 1], m[N + 1][N + 1]; // m_ij is partial LCS between i to j.
	for (int i = 1; i <= n; i++) cin >> p[i - 1] >> p[i];

	for (int i = 1; i <= n; i++) m[i][i] = 0;
	for (int l = 2; l <= n; l++) { // l is a length of partial LCS.
		for (int i = 1; i <= n - l + 1; i++) {
			int j = i + l - 1;
			m[i][j] = INT_MAX;
			for (int k = i; k <= j - 1; k++) {
				m[i][j] = min(m[i][j], m[i][k] + m[k + 1][j] + p[i - 1] * p[j] * p[k]);
			}
		}
	}
	cout << m[1][n] << endl;

	return 0;
}

C++: #define _CRT_SECURE_NO_WARNINGS
#define _USE_MATH_DEFINES
#include <iostream>
#include <cstdlib>
#include <string>
#include <cstdio>
#include <algorithm>
#include <cmath>
#include <vector>
#include <set>
#include <random>
#include <map>

using namespace std;

int LCS[1010][1010] = {};

int LCSLength(string strX,string strY) {

    int strXSize = strX.length();
    int strYSize = strY.length();
    for (int i = 0; i < strXSize + 1; i++) {
	for (int j = 0; j < strYSize + 1; j++) {
	    if (i == 0 || j == 0) {
		LCS[i][j] = 0;
	    }
	}
    }

    for (int i = 1; i < strXSize + 1; i++) {
	for (int j = 1; j < strYSize + 1; j++) {

	    //LCS[i]==LCS[j]
	    if (strX[i - 1] == strY[j - 1]) {
		LCS[i][j] = LCS[i - 1][j - 1] + 1;
	    }
	    else {
		LCS[i][j] = max(LCS[i][j - 1], LCS[i - 1][j]);
	    }
	}
    }

    return LCS[strXSize][strYSize];
}

int main() {

    //cin.tie(0);
    //ios::sync_with_stdio(false);

    int q; scanf("%d", &q);

    string strX;
    string strY;
    while (q-- > 0) {
	cin >> strX;
	cin >> strY;
	printf("%d\n", LCSLength(strX, strY));
    }



    return 0;

}

C++: #include<iostream>
#include<string>
int main()
{
  int n;
  int an[1000];
  int l=0;
  std::cin>>n;
  std::string x;
  std::string y;
  int ans[1001][1001];
  int j,k;
  for(int i=0;i<n;i++){
    std::cin>>x;
    std::cin>>y;
    for(int j=0;j<=1000;j++){
      for(int k=0;k<=1000;k++){
	ans[j][k]=0;
      }
    }
    for(int j=1;j<=x.size();j++){
      for(int k=1;k<=y.size();k++){
	if(x[j]==y[k]){
	  ans[j][k]=ans[j-1][k-1]+1;
	}else{
	  if(ans[j][k-1]>ans[j-1][k]){
	    ans[j][k]=ans[j][k-1];
	  }else{
	    ans[j][k]=ans[j-1][k];
	  }
	}
      }
    }
    std::cout<<ans[x.size()-1][y.size()-1]<<'\n';  
  }
  return 0;
}