Go: package main

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

//Util
func nextStr() string {
	sc.Scan()
	return sc.Text()
}

func nextInt() int {
	sc.Scan()
	i, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}
	return i
}

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

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

func absInt(a int) int {
	if a >= 0 {
		return a
	} else {
		return -a
	}
}

func absFloat64(a float64) float64 {
	if a >= 0 {
		return a
	} else {
		return -a
	}
}

func minFloat64(a, b float64) float64 {
	if a > b {
		return b
	} else {
		return a
	}
}

func str2Int(s string) int {
	n, _ := strconv.Atoi(s)
	return n
}

//Main
var sc = bufio.NewScanner(os.Stdin)
var q int
var X, Y string

func lcs(X, Y string) int {
	lenX := len(X)
	lenY := len(Y)
	dp := make([][]int, lenX+1)
	for i := 0; i < lenX+1; i++ {
		dp[i] = make([]int, lenY+1)
	}

	res := 0
	for i := 1; i < lenX+1; i++ {
		for j := 1; j < lenY+1; j++ {
			if X[i-1] == Y[j-1] {
				dp[i][j] = dp[i-1][j-1] + 1
			} else {
				dp[i][j] = maxInt(dp[i-1][j], dp[i][j-1])
			}
			//fmt.Println(dp)
			res = maxInt(res, dp[i][j])
		}

	}
	return res
}

func main() {
	sc.Split(bufio.ScanWords)
	q = nextInt()

	for i := 0; i < q; i++ {
		X = nextStr()
		Y = nextStr()

		fmt.Println(lcs(X, Y))
	}
}

C++: #include <iostream>
#include <string>
#include <algprithm>
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++ ) {
		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>
using namespace std;
#define int long long   // <-----!!!!!!!!!!!!!!!!!!!

#define rep(i,n) for (int i=0;i<(n);i++)
#define rep2(i,a,b) for (int i=(a);i<(b);i++)
#define rrep(i,n) for (int i=(n)-1;i>=0;i--)
#define rrep2(i,a,b) for (int i=(a)-1;i>=b;i--)
#define all(a) (a).begin(),(a).end()
#define rall(a) (a).rbegin(),(a).rend()
#define printV(v) for(auto x : v){cout << x << " ";} cout << endl
#define printVS(vs) for(auto x : vs){cout << x << endl;}
#define printVV(vv) for(auto v : vv){for(auto&& x : v){cout << x << " ";}cout << endl;}
#define printP(p) cout << p.first << " " << p.second << endl
#define printVP(vp) for(auto p : vp) printP(p);

typedef long long ll;
typedef pair<int, int> Pii;
typedef tuple<int, int, int> TUPLE;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<vvi> vvvi;
typedef vector<Pii> vp;
typedef vector<vector<int>> Graph;
const int inf = 1e9;
const int mod = 1e9 + 7;

int LCS(string s, string t) {
    int n = s.size();
    int m = t.size();
    s = "#" + s;
    t = "#" + t;

    vvi dp(n + 1, vi(m + 1));
    dp[0][0] = 0;

    rep2(i, 1, n + 1) {
        rep2(j, 1, m + 1) {
            if (s[i] == t[j]) {
                dp[i][j] = max(dp[i][j], dp[i - 1][j - 1] + 1);
            }
            dp[i][j] = max(dp[i][j], dp[i][j - 1]);
            dp[i][j] = max(dp[i][j], dp[i - 1][j]);
        }
    }

    return dp[n][m];
}

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

    int q;
    cin >> q;
    rep(i, q) {
        string s, t;
        cin >> s >> t;
        cout << LCS(s, t) << endl;
    }

}