Go: package main

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

// define
var (
	sc = bufio.NewScanner(os.Stdin)
)

func bordersInt(in_map [][]int, invalid int) [][]int{
	H, W := len(in_map), len(in_map[0])
	out_map := make([][]int, H+2)
	for h:=0; h<H+2; h++ {
		out_map[h] = make([]int, W+2)
		for w:=0; w<W+2; w++ {
			out_map[h][w] = invalid
		}
	}
	for h:=0; h<H; h++{
		for w:=0; w<W; w++{
			out_map[h+1][w+1] = in_map[h][w] 
		}
	}
	return out_map
}

func bordersString(in_map [][]string, invalid string) [][]string{
	H, W := len(in_map), len(in_map[0])
	out_map := make([][]string, H+2)
	for h:=0; h<H+2; h++ {
		out_map[h] = make([]string, W+2)
		for w:=0; w<W+2; w++ {
			out_map[h][w] = invalid
		}
	}
	for h:=0; h<H; h++{
		for w:=0; w<W; w++{
			out_map[h+1][w+1] = in_map[h][w] 
		}
	}
	return out_map
}

func scanIntLine(len int) []int{
	arr := make([]int, len)
	for i:=0; i<len; i++{
		sc.Scan()
		tmp, err := strconv.Atoi(sc.Text())
		if err == nil{
			arr[i] = tmp
		}
	}
	return arr
}

func scanStringLine(len int) []string{
	arr := make([]string, len)
	for i:=0; i<len; i++{
		sc.Scan()
		arr[i] = sc.Text()
	}
	return arr
}

func scanIntSplit(len int) []int{
	arr := make([]int, len)
	sc.Scan()
	for i, v := range strings.Split(sc.Text(), " "){
		tmp, err := strconv.Atoi(v)
		if err == nil{
			arr[i] = tmp
		}
	}
	return arr
}

func maxInt(args... int) int{
	sort.Ints(args)
	return args[len(args)-1]
}

func main(){
	buf := make([]byte, 0)
    sc.Buffer(buf, 1000000009)
	var n int 
	fmt.Scan(&n)
	dp := make([][]int, 1003)
	for i:=0; i<1003; i++ {
		dp[i] = make([]int, 1003)
	}
	input_lines := scanStringLine(2*n)
	for i:=0; i<n; i++ {
		S, T := input_lines[2*i], input_lines[2*i+1]
		lenS, lenT := len(S), len(T)
		for i:=1; i<lenS+1; i++ {
			for j:=1; j<lenT+1; j++ {
				if S[i-1] == T[j-1] {
					dp[i][j] = maxInt(dp[i-1][j-1]+1, dp[i-1][j], dp[i][j-1])
				} else {
					dp[i][j] = maxInt(dp[i-1][j], dp[i][j-1])
				}
			}
		}
		fmt.Println(dp[lenS][lenT])
	}
}

C++: #include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <iostream>
#include <string>
#include <vector>
#include <map>
#include <set>
#include <stack>
#include <list>
#include <queue>
#include <deque>
#include <algorithm>
#include <numeric>
#include <utility>
#include <complex>
#include <functional>
#include <climits>

using namespace std;
int c[1001][1001];

int main() {
	int n;
	cin >> n;
	for (size_t r = 0; r < n; r++)
	{
		string s, t;
		cin >> s >> t;
		int p = s.size();
		int q = t.size();
		for (size_t i = 1; i < p+1; i++)
		{
			for (size_t j = 1; j < q+1; j++)
			{
				if(s[i-1] == t[j-1]) {
					c[i][j] = c[i-1][j-1] + 1;
				} else {
					c[i][j] = max(c[i-1][j], c[i][j-1]);
				}
			}
			
		}
		cout << c[p][q] << endl;
	}
	
}

C++: #include<iostream>
#include<cstdio>
#include<cstring>
#define _A_ true
using namespace std;
 
int main(){
  int n,AC=0;
  int dp[1010][1010];
  char A[1500],B[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;
 
    for(int i=0;i<strlen(A);i++){
      for(int j=0;j<strlen(B);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[strlen(A)][strlen(B)]);
    AC++;
  }
  return 0;
}

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

string a,b;
int A[1002][1002];

int lcs () {
    int ath = a.length(), bth = b.length();
    int i, j;
    for ( i = 0; i < ath; i++ ) A[i][0] = 0;
    for ( j = 0; j < bth; j++ ) A[0][j] = 0;

    for ( i = 1; i <= ath; i++ ) {
        for ( j = 1; j <= bth; j++ ) {
            if ( a[i - 1] == b[j - 1] ) A[i][j] = A[i-1][j-1] + 1;
            else if ( A[i][j-1] > A[i-1][j] ) A[i][j] = A[i][j-1];
            else A[i][j] = A[i-1][j];
        }
    }

    return A[i-1][j-1];
}

int main()
{
    int n;
    cin >> n;
    while ( n-- ) {
        cin >> a >> b;
        cout << lcs() << endl;
    }

    return 0;
}

C++: #include<iostream>
#include<iomanip>
#include<algorithm>
#include<bitset>
#include<cctype>
#include<climits>
#include<cmath>
#include<cstdio>
#include<cstring>
#include<deque>
#include<list>
#include<map>
#include<set>
#include<stack>
#include<string>
#include<sstream>
#include<queue>
#include<vector>
using namespace std;

#define MAX 1001

static int dp[MAX][MAX];

int main() {
	int q; cin >> q;
	while (q--) {
		memset(dp, 0, size(dp));
		string X, Y; cin >> X >> Y;
		for (int i = 1; i <= X.size(); i++) {
			for (int j = 1; j <= Y.size(); j++) {
				if (X[i - 1] == Y[j - 1]) {
					//cout << i << j << X[i - 1] << endl;
					dp[i][j] = dp[i - 1][j - 1] + 1;
				}
				else {
					dp[i][j] = max(
						dp[i - 1][j],
						dp[i][j - 1]
					);
				}
			}
		}
		//for (int i = 0; i <= Y.size(); i++) {
		//	for (int j = 0; j <= X.size(); j++) {
		//		cout << dp[j][i] << " ";
		//	}
		//	cout << endl;
		//}
		cout << dp[X.size()][Y.size()] << endl;

	}

	return 0;
}

C++: // ALDS1_10_C.cpp
// Dynamic Programming - Longest Common Subsequence

#include <iostream>
#include <vector>
#include <string>
using namespace std;

int LCS(string s, string t)
{
    int res = 0;
    if (s.empty() || t.empty())
        return res;
    int s_len = s.size();
    int t_len = t.size();
    int len = min(s_len, t_len);
//    int lcs[s_len][t_len];
    vector<vector<int>> lcs(s_len, vector<int>(t_len));
    bool found = false;
    for (int i = 0; i < s_len; i++) {
        if (s[i] == t[0] || found) {
            lcs[i][0] = 1;
            found = true;
        }
    }
    found = false;
    for (int j = 0; j < t_len; j++) {
        if (s[0] == t[j] || found) {
            lcs[0][j] = 1;
            found = true;
        }
    }
    for (int i = 1; i < s_len; i++) {
        for (int j = 1; j < t_len; j++) {
            if (s[i] == t[j]) {
                lcs[i][j] = 1 + lcs[i-1][j-1];
            }
            else {
                lcs[i][j] = max(lcs[i-1][j], lcs[i][j-1]);
            }
        }
    }
    return lcs[s_len - 1][t_len - 1];
}

int main()
{
    int n;
    cin >> n;
    string s, t;
    while (n--) {
        cin >> s >> t;
        int res = LCS(s, t);
        cout << res << endl;
    }
    return 0;
}

C++: #include <iostream>
#include <string>
using namespace std;
int main(void){
    int n;
    cin >> n;
    for(int i = 0;i < n;i++){
        string X,Y;
        cin >> X >> Y;
        int L[X.length()+10][Y.length()+10];
        for(int j = 0;j < X.length()+10;j++){
            for(int k = 0;k < X.length()+10;k++){
                L[j][k] = 0;
            }
        }
        for(int j = 1;j<=X.length();j++){
            for(int k = 1;k<=Y.length();k++){
                if(Y[k] == X[j]){
                    L[j][k] = 1+L[j-1][k-1];
                }
                else{
                    L[j][k] = max(L[j-1][k],L[j][k-1]);
                }
            }
        }
        cout << L[X.length()][Y.length()] << endl;
    }
return 0;
}

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

int main(){
  int q, cnt, max=0;
  string str1, str2;
  char ch1, ch2;
  cin >> q;
  for(int i=0;i<q;i++){
    cin >> str1 >> str2;
    //cout << "cin >> str1 >> str2" << endl;
    for(int j=0;j<(int)str1.size();j++){
      for(int k=0;k<(int)str2.size();k++){
	//cout << "j = " << j << ", k = " << k << endl;
        cnt = 0;
	int l = 0;
	while(1){
	      //str1[j+l] || str2[k+l] || str1[j+l] == str2[k+l]){
	  ch1 = str1[j+l];
	  //  cout << ch1 << " ";
	  ch2 = str2[k+l];
	  //  cout << ch2 <<endl;
	  if(ch1 == ch2 && ch1 != '\0'){
     	    cnt++;
	    l++;
	    //	    cout << "一致" << endl;
	  }else break;
	}
	if(cnt > max) max = cnt;
      }
    }
    cout << max << endl;
  }
}