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++: def lcs(l1,l2):
    dp=[[0 for x in range(len(l2)+1)] for y in range(len(l1)+1)]

    for i in range(1,len(l1)+1):
        for j in range(1,len(l2)+1):
            if l1[i-1]==l2[j-1]:
                dp[i][j]=dp[i-1][j-1]+1
            else:
                dp[i][j]=max(dp[i-1][j],dp[i][j-1])
                
    return dp[len(l1)][len(l2)]


a=[]
n=int(input())
for i in range(n):
    l1=list(input())
    l2=list(input())
    a+=[lcs(l1,l2)]

for i in range(n):
    print(a[i])

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

static const long N = 1000;

long lcs(string X, string Y){
	long c[N + 1][N + 1];
	long m = X.size();
	long n = Y.size();
	long maxl = 0;
	X = ' ' + X;
	Y = ' ' + Y;
	for (long i = 1; i <= m; i++) c[i][0] = 0;
	for (long j = 1; j <= n; j++) c[0][j] = 0;

	for (long i = 1; i <= m; i++){
		for (long 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 = c[i][j];
		}
	}

	return maxl;
}

int main(){
	string s1, s2;
	long n;
	cin >> n;
	for (long i = 0; i < n; i++){
		cin >> s1 >> s2;
		cout << lcs(s1, s2) << endl;
	}
	return 0;
}

C++: #include <stdio.h>

int score[1010][1010];

int max2 (int a, int b){
  if (a >= b) return a;
  else return b;
}

int len_of_str(const char s[]){
  int num = 0;

  while(s[num]) num++;

  return num;
}


int main() {
  char a[1010];
  char b[1010];
  int datanum;
  scanf("%d",&datanum);
  for(int c = 0; c < datanum; c++){

  scanf("%999s",a);
  scanf("%999s",b);
  int num1 = len_of_str(a);
  int num2 = len_of_str(b);


  for(int i = num1; i > 0; i--) a[i] = a[i - 1];
  a[0] = ' ';
  for(int j = num2; j > 0; j--) b[j] = b[j - 1];
  b[0] = ' ';

  for(int i = 0; i <= num1; i++) score[i][0] = 0;
  for(int j = 0; j <= num2; j++) score[0][j] = 0;

  int maximum = 0;

  for(int i = 1; i<= num1; i++){
    for (int j = 1; j <= num2; j++){
      if (a[i] == b[j])score[i][j] = score[i-1][j-1] + 1;
      else if (a[i] != b[j]) score[i][j] = max2(score[i][j-1],score[i-1][j]);
      maximum = max2(maximum,score[i][j]);
    }
  }



  printf("%d\n",maximum);
}
  return 0;
}

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

using namespace std;
static const int N = 1000;

int lenCommon(string s1, string s2)
{
	int m = s1.size();
	int n = s2.size();
	int len = max(m, n);
	vector<vector<int> > dp(N+1, vector<int>(N+1, 0));

	//s1 = " " + s1;
	//s2 = " " + s2;

	//for (int i = 0; i <= len; ++i) dp[i][0] = 0;
	//for (int i = 0; i <= len; ++i) dp[0][i] = 0;

	int ret = 0;
	for (int i = 1; i <= m; ++i)
	{
		for (int j = 1; j <= n; ++j)
		{
			if (s1[i - 1] == s2[j - 1])
				dp[i][j] = dp[i - 1][j - 1] + 1;
			else
				dp[i][j] = max(dp[i - 1][j], dp[i][j - 1]);

			ret = max(ret, dp[i][j]);
		}
	}
	return ret;
}

int main()
{
	string s1, s2;
	int num; cin >> num;
	for (int i = 0; i < num; ++i)
	{
		cin >> s1 >> s2;
 		int res = lenCommon(s1, s2);
		cout << res << endl;
	}
}

C++: #include<stdio.h>
??
int hantei(char x[], char y[]) {
????int xn = 0, yn = 0, flag = 0, i, j, max = 0;
????int c[1001][1001];
??????
????while (flag == 0)
????{
????????if (x[xn] != '\0')
????????{
????????????xn++;
????????}
????????else
????????{
????????????flag = 1;
????????}
????}
??????
????flag = 0;
??????
????while (flag == 0)
????{
????????if (y[yn] != '\0')
????????{
????????????yn++;
????????}
????????else
????????{
????????????flag = 1;
????????}
????}
????for (i = 1; i < xn + 1; i++) c[i][0] = 0;
????for (j = 1; j < yn + 1; j++) c[0][j] = 0;
??????
????for (i = 1; i < xn + 1; i++)
????{
????????for (j = 1; j < yn + 1; j++)
????????{
????????????if (x[i - 1] == y[j - 1])
????????????{
????????????????c[i][j] = c[i - 1][j - 1] + 1;
????????????}
????????????else if (c[i - 1][j] >= c[i][j - 1])
????????????{
????????????????c[i][j] = c[i - 1][j];
????????????}
????????????else
????????????{
????????????????c[i][j] = c[i][j - 1];
????????????}
????????????if (max < c[i][j]) max = c[i][j];
????????}
????}
??????
????return max;
}
??
int main(void) {
????char x[1000], y[1000];
????int q, i;
??????
????scanf("%d", &q);
??????
????for (i = 0; i < q; i++)
????{
????????scanf("%s", x);
????????scanf("%s", y);
????????printf("%d\n", hantei(x, y));
????}
??????
????return 0;
}

C++: #include <iostream>
#include <string>
#include <cstdio>
#include <vector>
#include <queue>
#include <map>
using namespace std;

bool findSubStr(string& shortword, vector<vector<int> >& charMap) {
	int i,j;
	j=0;
	for(i=0; i<(int)shortword.size(); ++i) {
		if(charMap[shortword[i]-'a'].empty()) return false;
		auto itr=charMap[shortword[i]-'a'].begin();
		while(itr!=charMap[shortword[i]-'a'].end()) {
			if(*itr<j) {
				++itr;
			} else {
				break;
			}
		}
		if(itr==charMap[shortword[i]-'a'].end()) return false;
		j=*itr;
	}
	return true;
}

int longestSQ(string& shortword, string& longword) {
	int i,j;
	string tempstr,prestr;
	vector<vector<int> > charMap(26);
	queue<string> targetword;
	map<string,bool> inqueue;
	for(i=0; i<(int)longword.size(); ++i) {
		charMap[longword[i]-'a'].push_back(i);
	}
	targetword.push(shortword);
	while(!targetword.empty()) {
		tempstr=targetword.front();
		if(findSubStr(tempstr,charMap)) return (int)tempstr.size();
		j=(int)tempstr.size();
		for(i=0; i<j; ++i) {
				tempstr=targetword.front();
				if(i==0 || tempstr[i]!=tempstr[i-1]) {
					tempstr.erase(tempstr.begin()+i);
					if(inqueue.find(tempstr)==inqueue.end()) {
						targetword.push(tempstr);
						inqueue[tempstr]=true;
					}
				}
		}
		targetword.pop();
	}
	return 0;
}

int main() {
	int i,q;
	cin >> q;
	string wordA,wordB;
	for(i=0; i<q; ++i) {
		cin >> wordA >> wordB;
		if(wordA.size()<wordB.size()) {
			printf("%d\n",longestSQ(wordA,wordB));
		} else {
			printf("%d\n",longestSQ(wordB,wordA));
		}
	}
	return 0;
}