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.size();
    int n = Y.size();

    X = ' ' + X;
    Y = ' ' + Y;

    int maxl = 0;

    // Initialize
    for (int i = 0; i <= m; i++) c[i][0] = 0;
    for (int j = 0; 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 <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 <bits/stdc++.h>
typedef long long ll;
using namespace std;
#define repr(i,a,b) for(int i=a;i<b;i++)
#define rep(i,n) for(int i=0;i<n;i++)
#define invrepr(i,a,b) for(int i=b-1;i>=a;i--)
#define invrep(i,n) invrepr(i,0,n)
#define repitr(itr,a) for(auto itr=a.begin();itr!=a.end();++itr)
const int MOD=1e9+7;


int main() {
    ios_base::sync_with_stdio(false);

    int t;
    cin >> t;
    rep(k,t) {
        string x1,x2;
        cin >> x1 >> x2;
        int n=x1.size(),m=x2.size();
        vector<vector<int>> dp(n+1,vector<int>(m+1));
        rep(i,n) {
            rep(j,m) {
                if (x1[i]==x2[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[n][m] << endl;
    }

    return 0;   
}

C++: #include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;

int main(){
  int n;
  char x[1000],y[1000];
  int dp[1001][1001];
  //load n;
  cin >>n;
  for(int i=0;i<n;i++){
    //load string
    scanf("%s",x);
    scanf("%s",y);
    //dp
    for(int j=0;j<strlen(x);j++){
      for(int k=0;k<strlen(y);k++){
	if(x[j]==y[k]){
	  dp[j+1][k+1]=dp[j][k]+1;
	}

	else{
	  if(dp[j][k+1]>dp[j+1][k]){
	    dp[j+1][k+1]=dp[j][k+1];
	  }

	  else{
	    dp[j+1][k+1]=dp[j+1][k];
	  }


	}
      }
    }

  }
  cout <<dp[strlen(x)][strlen(y)]<<endl;

  return 0;
}

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

void lcs(string X, string Y) {
	int xLength = X.size();
	int yLength = Y.size();

	int dp[xLength + 1][yLength + 1];  
	int i,j;
	// initialize dp[][]
	for (i = 1; i <= xLength; i++)
		dp[i][0] = 0;
	for (i = 1; i <= yLength; i++)
		dp[0][i] = 0;

	for (i = 1; i <= xLength; i++){
		for (j = 1; j <= yLength; j++){
			// Because the original string is 0-based , so subtracted from 1
			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]);
			}
		}
	}

	// testing code: print out the dp[][]
	// cout << "j";
	// for (j = 1; j <= yLength; j++)
	// 	cout << ' ' << j ;
	// cout << endl;
		

	// for (i = 1; i <= xLength; i++){
	// 	cout << i << '.';
	// 	for (j = 1; j <= yLength; j++){
	// 		cout << dp[i][j] << ' ';
	// 	}
	// 	cout << endl;
	// }

	cout << dp[xLength][yLength] << endl;
}

int main() {
	int n , i;
	string X, Y;

	cin >> n;
	for (i = 0 ; i < n; i++ ) {
		cin >> X;
		cin >> Y;
		lcs(X, Y);
	}

	return 0;

}

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

using namespace std;

int main()
{
  int n;
  string a,b;
  cin>>n;
  for(int i=0;i<n;i++){
    cin>>a>>b;
    int f[a.size()+1][b.size()+1];
    for(int i=0;i<a.size()+1;i++){
      for(int j=0;j<b.size()+1;j++){
	f[i][j]=0;
      }
    }

    for(int j=1;j<a.size()+1;j++){
      for(int k=1;k<b.size()+1;k++){
	if(a[j-1]==b[k-1]){
	  f[j][k]=f[j-1][k-1]+1;
	}else{
	  f[j][k]=max(f[j-1][k],f[j][k-1]);
	}
      }
    }
    /*
    for(int j=0;j<b.size()+1;j++){
      for(int i=0;i<a.size()+1;i++){
	cout<<f[j][i]<<" ";
      }
      cout<<endl;
    }
    */
    cout<<f[a.size()][b.size()]<<endl;
  }
  return 0;
}

C++: /* test */
#include <bits/stdc++.h>
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++) c[i][0] = 0;
    for(int k=1;k<=n;k++) c[0][k] = 0;
 
    for(int i=1;i<=m;i++){
        for(int k=1;k<=n;k++){
            if(X[i]==Y[k]){
                c[i][k] = c[i-1][k-1] + 1;
            } else {
                c[i][k] = max(c[i-1][k],c[i][k-1]);
            }
            maxl = max(maxl,c[i][k]);
        }
    }
 
    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<algorithm>
usig 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++)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 <algorithm>
using namespace std;
int main(){
	int q;	cin>>q;
	string a,b;
	while(q--){
		cin>>a;
		cin>>b;
		int data[a.size()+1]={};
		for(int i=0;i<b.size();i++){
			for(int j=0;j<a.size();j++){
				if(a[j]==b[i]){
					for(int k=j;k>=0;k--){
						data[j+1]=max(data[j+1],data[k]+1);
					}
				}
			}
		}
		int ans=0;
		for(int i=1;i<=a.size();i++){
			ans=max(ans,data[i]);
		}
		cout<<ans<<endl;
	}
	return 0;
}