Go: package main

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

func getScanner(fp *os.File) *bufio.Scanner {
	scanner := bufio.NewScanner(fp)
	scanner.Split(bufio.ScanWords)
	scanner.Buffer(make([]byte, 500001), 500000)
	return scanner
}

func getNextString(scanner *bufio.Scanner) string {
	scanner.Scan()
	return scanner.Text()
}

func getNextInt(scanner *bufio.Scanner) int {
	i, _ := strconv.Atoi(getNextString(scanner))
	return i
}

func main() {
	fp := os.Stdin
	if len(os.Args) > 1 {
		fp, _ = os.Open(os.Args[1])
	}

	scanner := getScanner(fp)
	writer := bufio.NewWriter(os.Stdout)

	n := getNextInt(scanner)
	for i := 0; i < n; i++ {
		x := getNextString(scanner)
		y := getNextString(scanner)

		fmt.Fprintln(writer, lcs(x, y))
	}

	writer.Flush()
}

func lcs(x, y string) int {
	lx := len(x)
	ly := len(y)
	dp := make([][]int, lx+1)
	for i := 0; i <= lx; i++ {
		dp[i] = make([]int, ly+1)
	}
	for i := 0; i < lx; i++ {
		for ii := 0; ii < ly; ii++ {
			if x[i] == y[ii] {
				dp[i+1][ii+1] = dp[i][ii] + 1
				continue
			}
			dp[i+1][ii+1] = dp[i][ii+1]
			if dp[i+1][ii] > dp[i+1][ii+1] {
				dp[i+1][ii+1] = dp[i+1][ii]
			}
		}
	}
	return dp[lx][ly]
}

C++: #include <algorithm>
#include <cassert>
#include <cmath>
#include <cstdio>
#include <deque>
#include <iomanip>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <string>
#include <vector>

using namespace std;

#define pb push_back

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> i_i;
typedef pair<i_i, int> p_i;
typedef vector<int> vi;
typedef vector<vector<int> > vvi;
template<class T> using vv=vector<vector< T > >;

int main() {
  int t;
  cin >> t;
  vi results;
  for (int dataset = 0 ; dataset < t ; dataset++) {
    string a, b;
    cin >> a;
    cin >> b;
    vvi len(a.length()+1, vi(b.length()+1, 0));
    for (int ia = 0 ; ia < a.length() ; ia++) {
      for (int ib = 0 ; ib < b.length() ; ib++) {
        if (a[ia] == b[ib]) {
          len[ia+1][ib+1] = len[ia][ib]+1;
        } else {
          len[ia+1][ib+1] = max(len[ia+1][ib], len[ia][ib+1]);
        }
      }
    }
    results.pb(len[a.length()][b.length()]);
  }

  for (int it = 0 ; it < t ; it++) {
    printf("%d\n", results[it]);
  }

  return 0;
}

C++: #include <bits/stdc++.h>
#define rep(i,n) for (int i = 0; i < (n); i ++)
using namespace std;
typedef long long ll;
typedef pair<ll,ll> PL;
typedef pair<int,int> P;
const int INF = 1e9;
const int MOD = 17;
const vector<int> dy = {-1,0,1,0};
const vector<int> dx = {0,1,0,-1};

void solve() {
    string S,T; cin >> S >> T;
    int N = S.size(),M = T.size();
    vector<vector<int>> dp(N + 1,vector<int>(M + 1,0));
    rep(i,N)rep(j,M) {
        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]);
    }
    printf("%d\n",dp[N][M]);
}

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

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], maxl = 0, i, j;
  int m = x.size();
  int n = y.size();

  x = ' ' + x;
  y = ' ' + y;
 
  for(i = 1; i <= m; i++) c[i][0] = 0;
  for(i = 1; i <= n; i++) c[0][i] = 0;

  for(i = 1; i <= m; i++){
    for(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 x, y;
  int q, i;

  cin >> q;
  
  for(i = 0; i < q; i++){
    cin >> x >> y;
    cout << lcs(x, y) << endl;
  }
  return 0;
}

C++: #include <utility>
#include <algorithm>
#include <iostream>
#include <string>
#include <stack>
#include <cstdlib>


using namespace std;

int Q;


int main(){
  cin >> Q;
  string X,Y;
  int L[1010][1010]={0};
  int len = 0;
  for(int q=0;q<Q;++q){
    cin >> X;
    cin >> Y;
    len = X.length();
      for(int j=1;j<len+1;++j){//kkkkkkkkkkkkkkkkkkkkkkk
	for(int i=1;i<len+1;++i){
	  if(i <= 0 || j <= 0) L[i][j] = 0;
	  else if(X[i] == Y[j]) L[i][j] = 1 + L[i-1][j-1];
	  else L[i][j] = max(L[i][j-1],L[i-1][j]);
	}
      }

    cout << L[len][len] << endl;
  }
}

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

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

#define N 1000

int lcs(string X, string Y) {
  int m = X.size();
  int n = Y.size();
  int c[m + 1][n + 1];
  int maxlen = 0;
  X = ' ' + X;
  Y = ' ' + Y;
  c[0][0] = 0;
  FOR(i, 1, m + 1) c[i][0] = 0;
  FOR(j, 1, n + 1) c[0][j] = 0;

  FOR(i, 1, m + 1) {
    FOR(j, 1, n + 1) {
      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 maxlen;
}

int main(void) {
  string X, Y;
  int n; cin >> n;
  REP(i, n) {
    cin >> X >> Y;
    cout << lcs(X, Y) << endl;
  }
  return 0;
}

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

int lcs(string x, string y) {
	static int c[1001][1001];
	int m = x.size();
	int n = y.size();
	int max1 = 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]);
			max1 = max(max1, c[i][j]);

		}
	}
	return max1;
}

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<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;
}

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

using namespace std;

const int MAX_N = 160;

int LongestCommonSubsequence(string s1, string s2) {
    int N = (int) s1.size();
    int M = (int) s2.size();
    vector < vector < int > > dp(N + 10, vector < int > (M + 10, 0));
    for (int i = 0; i < N; i++) {
        for (int j = 0; j < M; j++) {
            if (s1[i] == s2[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]);
            }
        }
    }
    return dp[N][M];
}

int main(int argc, char const *argv[])
{
    int q, ans[MAX_N];
    cin >> q;
    for (int i = 0; i < q; ++i) {
        string a, b;
        cin >> a >> b;
        ans[i] = LongestCommonSubsequence(a,b);
    }

    for (int i = 0; i < q; ++i) {
        cout << ans[i] << endl;
    }
	return 0;
}