Go: package main

import "fmt"

func initialize_grid(width int,height int)[][]int{
	var grid [][]int
	for i:=0;i<height+1;i++{
		var grid_row  []int
		for j:=0;j<width+1;j++{
			grid_row = append(grid_row,0)
		}
		grid = append(grid,grid_row[:])
	}
	return grid
}

func ma(x int,y int)int{
	if x >= y{
		return x
	}else{
		return y
	}
}

func main()  {
	//Take input
	var num int
	var st1,st2 string
	var string_pairs [][]string
	fmt.Scan(&num)
	for i:=0;i<num;i++{
		var string_pair []string
		fmt.Scan(&st1)
		fmt.Scan(&st2)
		string_pair = append(string_pair,st1,st2)
		string_pairs = append(string_pairs,string_pair)
	}
	//DP
	//initialize grid
	for i:=0;i<num;i++{
		string_1 := string_pairs[i][0]
		string_2 := string_pairs[i][1]

		dp := initialize_grid(len(string_2),len(string_1))

		for j:=1;j<len(string_1)+1;j++{
			for k:=1;k<len(string_2)+1;k++{
				if string_1[j-1] == string_2[k-1]{
					dp[j][k] = dp[j-1][k-1] + 1
				}else{
					dp[j][k] = ma(dp[j-1][k],dp[j][k-1])
				}
			}
		}
		fmt.Println(dp[len(string_1)][len(string_2)])
	}
}

C++: #include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
const int maxx = 1010;
int c[maxx][maxx];

int lcs(char s1[],char s2[]) {
    int m = strlen(s1), n = strlen(s2);
    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 = 0; i < m; i++) {
        for (int j = 0; j < n; j++) {
            if (s1[i] == s2[j])
            c[i+1][j+1] = c[i][j] + 1;
            else
            c[i+1][j+1] = max(c[i][j+1], c[i + 1][j]);
        }
    }
    return c[m][n];
}
int main()
{
    char s1[maxx], s2[maxx];
    int t;
    scanf("%d", &t);
    for (int i = 0; i < t; i++) {
        scanf("%s %s", s1, s2);
        printf("%d\n",lcs(s1,s2));
    }
    
    return 0;
}

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

using namespace std;

string str1,str2;


int LCS(int i,int j){
  
  if(i==-1||j==-1){
    return 0;
  }else if(str1[i]==str2[j]){
    return LCS(i-1,j-1)+1;
  }else{
    return max(LCS(i-1,j),LCS(i,j-1));
  }
  
}

int main(){
  int N;
  
  cin >> N;
  for(int i=0;i<N;i++){
    cin >> str1 >> str2;
    cout << LCS(str1.size()-1,str2.size()-1) << 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 = 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 <utility>
using namespace std;
#define MAXQ 150
#define MAXL 1000

int main(){
    int n; cin >> n;
    pair<string, string> pairs[MAXQ];
    for(int i=0; i<n; ++i){
        cin >> pairs[i].first >> pairs[i].second;
    }
    
    for(int i=0; i<n; ++i){
        string str1, str2;
        str1 = pairs[i].first;
        str2 = pairs[i].second;
        int dp[MAXL][MAXL];
        for(int r=0; r<=str1.size(); ++r){
            dp[r][0] = 0;
        }
        for(int c=0; c<=str2.size(); ++c){
            dp[0][c] = 0;
        }
        for(int r=1; r<=str1.size(); ++r){
            for(int c=1; c<=str2.size(); ++c){
                int d = 0;
                if (str1[r-1] == str2[c-1]) d++;
                dp[r][c] = max(dp[r-1][c-1]+d, max(dp[r-1][c], dp[r][c-1]));
            }
        }
        cout << dp[str1.size()][str2.size()] << endl;
    }
}

C++: #include<iostream>
#include<string>
#include<math.h>
#include<algorithm>
#include<vector>
using namespace std;
#define rep(i, n) for(int i = 0; i < n; i++)
int main(){
    int n,dp[1001][1001];
    cin>>n;
    string x,y;
    rep(i,n){
        cin>>x>>y;
        rep(j,x.size()+1) rep(k,y.size()+1) dp[j][k]=0;
        rep(j,x.size()) rep(k,y.size()){
            if(x[j]==y[k]) dp[j+1][k+1]=max(max(dp[j][k]+1,dp[j+1][k]),dp[j][k+1]);
            else dp[j+1][k+1]=max(dp[j+1][k],dp[j][k+1]);
        }
        cout<<dp[x.size()][y.size()]<<endl;
    }
}

C++: //	created : 16/03/15
// 	author   : Rp7rf
#include <iostream>
#include <vector>
#include <algorithm>
#include <cstdio>
#include <cstring>
#include <set>
typedef long long ll;
typedef unsigned long long ull;
using namespace std;
#define rep(i,a) for(int i = 0 ; i < a ; i ++)
#define loop(i,a,b) for(int i = a ; i < b ; i ++)
#define vi vector<int>
#define mp make_pair
#define pb push_back
#define MOD 1000000007
#define INF 1e9


int main(void){
	int n;
	string s1,s2;
	cin>>n;
	int dp[1010][1010];
	rep(i,n){
		int ret = 0;
		cin>>s1>>s2;
		rep(i,s1.size()+1)dp[i][0] = 0;
		rep(j,s2.size()+1)dp[0][j] = 0;

		loop(i,1,s1.size()+1){
			loop(j,1,s2.size()+1){
				if(s1[i] == s2[j]){
					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]);
			}
		}
		cout<<ret<<endl;
	}
}

C++: #include<iomanip>
#include<limits>
#include<thread>
#include<utility>
#include<iostream>
#include<string>
#include<algorithm>
#include<set>
#include<map>
#include<vector>
#include<stack>
#include<queue>
#include<cmath>
#include<numeric>
#include<cassert>
#include<random>
#include<chrono>
using namespace std;
typedef unsigned long long int ull;
typedef long long int ll;
typedef pair<ll,ll> pll;
typedef pair<int,int> pi;
#define F first
#define S second
#define MK make_pair
const ll E=1e17+7;
const ll MOD=1000000007;






int main(){
    ll q;
    cin>>q;
    while(q--){
        
        
    string a,b;
    cin>>a>>b;
    
    vector<set<ll>> w(300);
    vector<vector<ll>> dp(2000);
    for(int i=0;i<dp.size();i++){dp[i].resize(2000,E);}
    
    for(int i=0;i<b.size();i++){
        w[b[i]].insert(i);
    }
    
    ll mx=-1;
    
    for(int i=0;i<a.size();i++){
        for(int t=0;t<b.size()+100;t++){
            if(t==0 && *w[a[i]].begin()<dp[i][t]){
                dp[i+1][t]=*w[a[i]].begin();
            }
            else if(w[a[i]].upper_bound(dp[i][t-1])!=w[a[i]].end() && *w[a[i]].upper_bound(dp[i][t-1])<dp[i][t]){
                dp[i+1][t]=*w[a[i]].upper_bound(dp[i][t-1]);
                mx=max(mx,(ll)t+1);
            }
            else{dp[i+1][t]=dp[i][t];}
        }
    }
    cout<<mx<<endl;
        
        
    }
    
    return 0;
}

C++: #include<stdio.h>
#include<string.h>
#include<algorithm>
using namespace std;

char a[1005],b[1005];
int n,c[1005][1005];

int lcs(){
    int n=strlen(a);
    int m=strlen(b);
    for(int i=0;i<n;i++) c[i][0]=0;
    for(int j=0;j<m;j++) c[0][j]=0;
    int ans=0;
    for(int i=0;i<n;i++){
        for(int j=0;j<m;j++){
            if(a[i]==b[j])
                c[i][j]=c[i-1][j-1]+1;
            else
                c[i][j]=max(c[i-1][j],c[i][j-1]);
            ans=max(c[i][j],ans);
        }
    }
    return ans;
}

int main(){
    scanf("%d",&n);
    for(int i=0;i<n;i++){
        memset(a,0,sizeof(a));
        memset(b,0,sizeof(b));
        memset(c,0,sizeof(c));
        scanf("%s%s",a,b);
        printf("%d\n",lcs());
    }
    return 0;
}