Go: package main

import (
	"fmt"
)

func main() {
	var q int
	fmt.Scan(&q)

	for i := 0; i < q; i++ {
		var x, y string
		fmt.Scan(&x)
		fmt.Scan(&y)

		xs := []rune(x)
		ys := []rune(y)

		xn := len(xs)
		yn := len(ys)
		dp := make([][]int, xn+1)
		for j := 0; j <= xn; j++ {
			dp[j] = make([]int, yn+1)
		}

		for j := 1; j <= xn; j++ {
			for k := 1; k <= yn; k++ {
				dp[j][k] = max(dp[j-1][k], dp[j][k-1])
				if xs[j-1] == ys[k-1] {
					dp[j][k] = max(dp[j][k], dp[j-1][k-1] + 1)
				} else {
					dp[j][k] = max(dp[j][k], dp[j-1][k-1])
				}
			}
		}
		fmt.Println(dp[xn][yn])
	}
}

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

C++: import sys

def dp_init(m, n):
    return [[0] * n] * m

def solve(str_a, str_b):
    dp = dp_init(len(str_a), len(str_b))
    return rec(len(str_a), len(str_b), str_a, str_b, dp)

def rec(i, j, str_a, str_b, dp):
    if i == 0 or j == 0:
        return 0
    if dp[i][j] > 0:
        return dp[i][j]
    if str_a[i-1] == str_b[j-1]:
        dp[i][j] = rec(i-1, j-1, str_a, str_b, dp) + 1
        return dp[i][j]
    dp[i][j] = max(rec(i, j-1, str_a, str_b, dp), rec(i-1, j, str_a, str_b, dp))
    return dp[i][j]

nb_pairs = int(input())
pairs = []
for i in range(0, nb_pairs):
    pairs.append((input(), input()))

for i in range(0, nb_pairs):
    str_a, str_b = pairs[i]
    print(solve(str_a, str_b))

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

using namespace std;



int n;
string a, b;
string x[10000], y[10000];




int main(){
  cin >> n;
  while(n != 0){
    n = n -1;
    int longest[1000][1000];
    cin >> a;
    cin >> b;
    a = ' ' + a;
    b = ' ' + b;
    int mm = 0;
    /*
    for(int i = 0; i < a.size(); ++i){
      for(int j = 0; j < b.size(); ++j){
        
        x[i] = a;
        y[j] = b;
      }
    }
    */
   //longest[0][0] =0;
   for(int i = 1; i <= a.size(); ++i){
     longest[i][0] = 0;
    }
   for(int j = 1; j <= b.size(); ++j){
     longest[0][j] = 0;
   }
    for(int i = 1; i <= a.size(); ++i){
      for(int j = 1; j <= b.size(); ++j){
        
        /*
        if(i <= 0 || j <=0){
          longest[i][j] = 0;
        }
        */
        if(a[i] == b[j]){
          longest[i][j] = 1 + longest[i-1][j - 1];
        }
        else{
          longest[i][j] = max(longest[i][j-1], longest[i-1][j]);
        }
        mm = max(mm, longest[i-1][j-1]);
      }
    }
    //cout << a[1] << endl;
    cout << mm << endl;
  }
}

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

using namespace std;

int lcs(string s1, string s2) {
    int c[1005][1005];
    int m = s1.length();
    int n = s2.length();
    s1 = " " + s1;
    s2 = " " + s2;
    int max1 = 0;
    for (int i = 0; i <= m; i++) {
        c[i][0] = 0;
    }
    for (int i = 0; i <= n; i++) {
        c[0][i] = 0;
    }
    for (int i = 1; i <= m; i++) {
        for (int j = 1; j <= n; j++) {
            if (s1[i] == s2[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() {
    int q;
    cin >> q;
    string s1, s2;
    for (int k = 0; k < q; k++) {
        cin >> s1;
        cin >> s2;
        cout << lcs(s1, s2) << endl;
    }

    return 0;
}

C++: #include<iostream>
#include<cmath>
#include<algorithm>
using namespace std;
int dp[1001][1001];
int n;
int strlen_1(char a[]){int len=0;while(a[len]!='\0')len++;return len;}
int solve(char a[],char b[])
{	
	
	int maxn=0;
	int len1=strlen_1(a),len2=strlen_1(b);
	

	for(int i=1;i<=strlen_1(a);i++)
		for(int j=1;j<=strlen_1(b);j++)
		{
			if(a[i-1]==b[j-1])
				dp[i][j]=dp[i-1][j-1]+1;
			else 
				dp[i][j]=max(dp[i-1][j],dp[i][j-1]);//这个只是表示某个状态的不是最大的，这个是自己设定的
			maxn=max(maxn,dp[i][j]);
		}
		return maxn;
		
		
	
}
char a[1001],b[1001];
int main()
{
	
	cin>>n;
	for(int i=0;i<n;i++)
	{
		cin>>a>>b;
		cout<<solve(a,b)<<endl;
	}
	return 0;
}

C++: #include<iostream>
#include<string>
#include<algorithm>
#include<cstdlib>
#include<cmath>
#include<vector>
#include<list>

using namespace std;

int n;
string x,y;

vector<vector<int> > q(1001,vector<int>(1001,-1));

int search(int i,int j){
  int ans;
  if(q[i][j] != -1) return q[i][j];
  if(i==0 || j==0) return 0;
  if( x[i] == y[j] ){
    ans=max( {search(i-1,j-1)+1,search(i-1,j),search(i,j-1)} );
    q[i][j]=ans;
    return ans;
  }
  else{
    ans=max( search(i-1,j),search(i,j-1) );
    q[i][j]=ans;
    return ans;
  }

}


int main(void){

  cin>>n;

  for(int i=0;i<n;i++){
    cin>>x;
    cin>>y;

    for(int ix=0;ix<1001;ix++){
      for(int iy=0;iy<1001;iy++){
        q[ix][iy]=-1;
      }
    }

    search( x.size(),y.size() );
    cout << q[x.size()][y.size()] << endl;
  }



  return 0;
}

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

using namespace std;

int main(void)
{
    int q;
    char x[1001], y[1001];
    int table[1001][1001];
    
    cin >> q;
    for (int i = 0; i < q; i++) {
	cin >> x >> y;
	int xl = strlen(x), yl = strlen(y);

	for (int i = 0; i < xl; i++)
	    table[i][0] = x[i] == y[0];
	for (int j = 0; j < yl; j++)
	    table[0][j] = x[0] == y[j];

	for (int i = 1; i < xl; i++)
	    for (int j = 1; j < yl; j++)
		if (x[i] == y[j])
		    table[i][j] = 1 + table[i-1][j-1];
		else
		    table[i][j] = max(table[i-1][j], table[i][j-1]);

	cout << table[xl - 1][yl - 1] << endl;
    }

    return 0;
}

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

string S,T;
int x[10000],y[10000];
int dp[10000][10000];
char U[5]="abcd";
int MAXN;

int main(){
	int q;
	cin>>q;
	for(int i=0;i<q;i++){
		MAXN=0;
		cin>>S>>T;
		for(int i=0;i<S.size();i++){
			for(int j=0;j<4;j++){
				if(S[i]==U[j]){
					x[i+1]=j;
				}
			}
		}
		for(int i=0;i<T.size();i++){
			for(int j=0;j<4;j++){
				if(T[i]==U[j]){
					y[i+1]=j;
				}
			}
		}
		for(int i=0;i<=T.size();i++){
			for(int j=0;j<=S.size();j++){
				if(i==0 || j==0){
					dp[i][j]=0;
				}
				else if(x[j]==y[i]){
					dp[i][j]=dp[i-1][j-1]+1;
				}
				else{
					dp[i][j]=max(dp[i][j-1],dp[i-1][j]);
				}
			}
		}
		for(int i=0;i<=T.size();i++){
			for(int j=0;j<=S.size();j++){
				MAXN=max(MAXN,dp[i][j]);
			}
		}
		cout<<MAXN<<endl;
	}
	return 0;
}

C++: #include <cstdio>
#include <cmath>
#define MAX 1001
using namespace std;

int Lcc(const char *X, const char *Y) {
    int lcc = 0;
    int dp[MAX][MAX];
    for (int i=0; i<MAX; i++)
        for (int j=0; j<MAX; j++) dp[i][j] = 0;

    int x=0, y=0;
    for (int i=0;;i++) {
        if (X[i] == ',') {x = i;break;}
        for (int j=0;;j++) {
            if (Y[j] == ',') {
                y = j;
                break;
            } else {
                if (X[i] == Y[j]) {
                    dp[i+1][j+1] = fmax(dp[i][j] + 1, dp[i+1][j]);
                } else {
                    dp[i+1][j+1] = fmax(dp[i+1][j], dp[i][j+1]);
                }
            }
        }
    }
    return dp[x-1][y-1];
}

int
main()
{
    int q;
    scanf("%d", &q);
    for (int i=0; i<(q); i++) {
        char X[MAX], Y[MAX];
        for (int i=0; i<MAX; i++) {
            X[i] = ','; Y[i] = ',';
        }
        scanf(" %s", X);scanf(" %s", Y);
        int LCC = Lcc(X, Y);
        printf("%d\n", LCC);
    }
    return 0;
}