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<iostream>
#include<cstdio>
#include<cstring>
#define _A_ true
using namespace std;
 
int main(){
  int n,AC=0,strA,strB;
  int dp[1010][1010];
  char *A = new char[1500];
  char *B = new char[1500];
 
  scanf("%d",&n);
  while(_A_){
    if(AC == n)break;
    scanf("%s",A);
    scanf("%s",B);
    for(int i=0;i<1010;i++)for(int j=0;j<1010;j++)dp[i][j]=0;
strA = strlen(A); 
strB = strlen(B);

    for(int i=0;i<strA;i++){
      for(int j=0;j<strB;j++){
    if(A[i] == B[j]){
      dp[i+1][j+1]=dp[i][j]+1;
    }
    else{
      if(dp[i+1][j] > dp[i][j+1]){
        dp[i+1][j+1]=dp[i+1][j];
      }
      else {
        dp[i+1][j+1] = dp[i][j+1];
      }
    }
      }
    }
    printf("%d\n",dp[strA][strB]);
    AC++;
  }
  delete [] A;
  delete [] B;
 
  return 0;
}

C++: #include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
const int N = 1010;
char A[N],B[N];
int dp[N][N];
void lcs(char A[],char B[]){
    int lenA = strlen(A+1);
    int lenB = strlen(B+1);
    
    for(int i=0;i<=lenA;i++){
        dp[i][0] = 0;
    }
    for(int i=0;i<lenB;i++){
        dp[0][i] = 0;
    }
    for (int i=1; i<=lenA; i++) {
        for(int j=1;j<=lenB;j++){
            if(A[i] == B[j]){
                dp[i][j] = dp[i-1][j-1] + 1;
            }
            else dp[i][j] = max(dp[i-1][j], dp[i][j-1]);
        }
    }
    printf("%d\n",dp[lenA][lenB]);
}

int main(){
    int n;
    scanf("%d",&n);
    for (int i=0; i<n; i++) {
        //从下标为1开始读入
        lcs(gets(A+1),gets(B+1));
    }
}

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

using namespace std;
 
 
int main(){
 
  string str1;
  string str2;
  int n,s1,s2;
  int c[1001][1001] = {{}};
  int max = 0;
 
  cin >> n;
 
  for(int i = 0;i < n;i++){
 
    cin >> str1 >> str2;
 
    str1 = ' ' + str1;
    str2 = ' ' + str2;
 
 
    s1 = str1.size();
    s2 = str2.size();
 
    for(int j = 1;j < s1;j++){
      for(int k = 1;k < s2;k++){
    if(str1[j] == str2[k]){
      c[j][k] = c[j - 1][k - 1] + 1;
      if(c[j][k] > max) max = c[j][k];
    }
    else if(c[j - 1][k] > c[j][k - 1]){
      c[j][k] =  c[j - 1][k];
    }
    else {
      c[j][k] = c[j][k - 1];
    }
      }
    }
 
 
    cout << max << endl;
       
    max = 0;
 
    for(int j = 0;j <= s1;j++){
      for(int k = 0;k <= s2;k++){
        c[j][k] = 0;
      }
    }
  }
}

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

#define MAX_X 1000
#define MAX_Y 1000
using namespace std;

string X, Y;
int dp[MAX_X + 1][MAX_Y + 1] = {0};

void solve() {
    for (int i = 0; i <= X.size(); ++i) {
        for (int j = 0; j <= Y.size(); ++j) {
            if (i == 0 || j == 0)
                dp[i][j] = 0;
            else if (X[i] == Y[j])
                dp[i][j] = max(dp[i - 1][j - 1] + 1, max(dp[i][j - 1], dp[i - 1][j]));
            else
                dp[i][j] = max(dp[i][j - 1], dp[i - 1][j]);
        }
    }

    return;
}

int main() {
    int q;
    cin >> q;
    for (int i = 0; i < q; ++i) {
        cin >> X >> Y;
        solve();
        printf("%d\n", dp[X.size()][Y.size()]);
    }
}

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

int lcs(string X, string Y) {
  int cs[1001][1001];
  int m = X.size();
  int n = Y.size();
  int answer = 0;
  for (int i = 1; i <= m; i++) cs[i][0] = 0;
  for (int j = 1; j <= n; j++) cs[0][j] = 0;

  for (int i = 1; i <= m; i++) {
    for (int j = 1; j <= n; j++) {
      if (X[i - 1] == Y[j - 1]) {
        cs[i][j] = cs[i - 1][j - 1] + 1;
      } else {
        cs[i][j] = max(cs[i - 1][j], cs[i][j - 1]);
      }
      answer = max(answer, cs[i][j]);
    }
  }

  return answer;
}

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

  int n;
  cin >> n;

  string X, Y;

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

  return 0;
}

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

int n;
string x, y;
bool mat[1000][1000];
int a[1000][1000];

int max(int i, int j) {
	int r = (!mat[i - 1][j] ? a[i - 1][j] : 0);
	r = ((!mat[i][j - 1] && a[i][j - 1] > r) ? a[i][j - 1] : r);
	return r > a[i - 1][j - 1] ? r : a[i - 1][j - 1];
}

int main(){
	cin >> n;
	for (int ia = 0; ia < n; ia++) {
		int ans = 0, p = 0;
		cin >> x >> y;
		for (int i = 0; i < x.length(); i++) {
			mat[i][0] = x[i] == y[0] ? true : false;
			a[i][0] = mat[i][0] ? 1 : 0;
		}
		for (int i = 1; i < y.length(); i++) {
			mat[0][i] = x[0] == y[i] ? true : false;
			a[0][i] = mat[0][i] ? 1 : 0;
		}
		for (int i = 1; i < x.length(); i++) {
			for (int j = 1; j < y.length(); j++) {
				mat[i][j] = x[i] == y[j] ? true : false;
				a[i][j] = max(i, j) + (mat[i][j] ? 1 : 0);
				if (a[i][j] > p) p = a[i][j];
			}
		}
		if (a[x.length() - 1][0] > p) p = a[x.length() - 1][0];
		if (a[0][y.length() - 1] > p) p = a[0][y.length() - 1];
		cout << p << endl;
	}


	return 0;
}