Go: ///
// File:  0528.go
// Author: ymiyamoto
//
// Created on Thu Mar 22 01:52:09 2018
//
package main

import (
	"bufio"
	"fmt"
	"os"
)

var S, T string
var dp [4001][4001]int

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

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	for {
		scanner.Scan()
		S = scanner.Text()
		if len(S) == 0 {
			return
		}

		scanner.Scan()
		T = scanner.Text()

		for i := range dp {
			for j := range dp[i] {
				dp[i][j] = 0
			}
		}

		dp[0][0] = 0
		for i := range S {
			for j := range T {
				if S[i] == T[j] {
					dp[i+1][j+1] = dp[i][j] + 1
				} else {
					dp[i+1][j+1] = 0
				}
			}
		}

		var m int
		for i := range dp {
			for j := range dp[i] {
				m = max(m, dp[i][j])
			}
		}
		fmt.Println(m)
	}
}

C++: #include <bits/stdc++.h>
using namespace std ;

#define pb(n) push_back(n)
#define fi first
#define se second
#define all(r) (r).begin(),(r).end()
#define gsort(st,en) sort((st),(en),greater<int>())
#define vmax(ary) *max_element(all(ary))
#define vmin(ary) *min_element(all(ary))
#define debug(x) cout<<#x<<": "<<x<<endl
#define fcout(n) cout<<fixed<<setprecision((n))
#define scout(n) cout<<setw(n)
#define vary(type,name,size,init) vector< type> name(size,init)

#define rep(i,n) for(int i = 0; i < (int)(n);++i)
#define REP(i,a,b) for(int i = (a);i < (int)(b);++i)
#define repi(it,array) for(auto it = array.begin(),end = array.end(); it != end;++it)
#define repa(n,array) for(auto &n :(array))

using ll = long long;
using vi = vector<int>;
using vl = vector<ll>;
using dict = map<string,int>;
using pii = pair<int,int> ;
using pll = pair<ll,ll> ;

const int mod = 1000000007;
constexpr int imax = ((1<<30)-1)*2+1 ;
constexpr int inf = 100000000;
constexpr double PI = acos(-1.0) ;
double eps = 1e-10 ;
const int dy[] = {-1,0,1,0};
const int dx[] = {0,-1,0,1};

inline bool value(int x,int y,int w,int h){
  return (x >= 0 && x < w && y >= 0 && y < h);
}

template<typename T>
void Unique(vector<T> &v){
  sort(all(v));
  v.erase(unique(all(v)),v.end());
}

template<typename T>
T ston(string& str, T n){
  istringstream sin(str) ;
  T num ;
  sin >> num ;
  return num ;
}

void Ans(bool f){
  if(f) cout << "YES"<<endl;
  else cout << "NO"<<endl;
}

int main(){
  cin.tie(0);
  ios::sync_with_stdio(false);
  string s,s2;
  while(cin >> s >> s2){
    ll ans = 0;
    rep(i,s.size()){
      ll len = 0;
      for(int j = 0; j < s2.size();){
        if(s[i+len] == s2[j+len]){
          len++;
          ans = max(len,ans);
          if(i+len >= s.size() || j+len >= s2.size()) break;
        }
        else{
          ++j;
          len = 0;
        }
      }
    }
    cout << ans << endl;
  }
  return 0;
}

C++: //JOI 0528 Common Sub-String
#include <iostream>
#include <string>
#include <algorithm>
using namespace std;
int main() {
	while(1){
		string s, t; int roop1=0, save=0, ans = 0;
		cin>>s;
		cin>>t;
		if(s==""){
		break;
		}
	for (int i = 0; i<s.size(); i++){
		for (int j = 0; j<t.size(); j++){
			if (s[i] == t[j]){
				roop1 = 0;
				save= 0;
				while (1){
					if (s[i + roop1] == 0 || t[j + roop1] == 0){
						break;
					}
					else{
						if (s[i + roop1] == t[j + roop1]){
							save += 1;
							roop1++;
						}
					else if (s[i + roop1] != t[j + roop1]){
							ans=max(ans,save);
							break;
						}
					}
				}
			}
		}
	}
	cout<<ans<<endl;
	}
	
	return 0;
}

C++: #include<stdio.h>
#include<string.h>
unsigned short d[4000][4000];
char a[4001],b[4001];
int i,j;

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

int main(){
	while(scanf("%s",a)!=EOF){
		scanf("%s",b);
		int al=strlen(a);
		int bl=strlen(b);
		for(i=0;i<al;i++)for(j=0;j<bl;j++)d[i][j]=0;
		for(i=0;i<al;i++)for(j=0;j<bl;j++){
			if(a[i]==b[j]){
				if(i>0&&j>0)d[i][j]=d[i-1][j-1]+1;
				else d[i][j]=1;
			}
			else{
				d[i][j]=0;
			}
		}
		/*for(i=0;i<strlen(a);i++){
			for(j=0;j<strlen(b);j++)printf("%d ",d[i][j]);
			printf("\n");
		}
		printf("\n");*/
		int ans=0;
		for(i=0;i<al;i++)for(j=0;j<bl;j++)ans=max(ans,d[i][j]);
		printf("%d\n",ans);
	}
	return 0;
}

C++: #include <iostream>
#include <string>
#include <algorithm>
using namespace std;
int main() {
	string s, t; int roop1, roop2 = 0, save[10000], ans = 0;
	while(cin.eof()){
	cin >> s >> t;
	for (int i = 0; i<s.size(); i++){
		for (int j = 0; j<t.size(); j++){
			if (s[i] == t[j]){
				roop1 = 0;
				save[roop2] = 0;
				while (1){
					if (s[i + roop1] == 0|| t[j + roop1] ==0){
						break;
					}
					else{
					if (s[i + roop1] == t[j + roop1]){
							save[roop2] += 1;
							roop1++;
							cout << save[roop2] << ' ';
						}
						else if (s[i + roop1] != t[j + roop1]){
							roop2++;
							break;
						}
					}
				}
			}
		}
	}
	sort(save, save + roop2 + 1);
	ans = save[roop2];
	cout << ans << endl;
	}
	return 0;
}

C++: #include <iostream>

#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define REP(i,j) FOR(i,0,j)

int dp[4001][4001];

int main(){
    std::string a, b;
    while(std::cin >> a >> b, !std::cin.eof()){
        REP(i, 4001){
            REP(j, 4001){
                dp[i][j] = 0;
            }
        }

        int res = 0;
        for(int i=a.size()-1;i>=0;i--){
            for(int j=b.size()-1;j>=0;j--){
                if(a[i] == b[j]){
                    dp[i][j] = std::max(1, dp[i+1][j+1] + 1);
                    res = std::max(dp[i][j], res);
                }else{
                    dp[i][j] = 0;
                }
            }
        }

        std::cout << res << std::endl;
    }

    return 0;
}

C++: #include <cstdio>
#include <iostream>
#include <stdlib.h>
#include <iomanip>
#include <string> 
#include <sstream>  
#include <vector> 
#include <time.h>
#include <algorithm>
#include <list>
#include <fstream>
#include <math.h>
using namespace std;
int main(){

	while(true){
		char A[4000],B[4000];
		cin >> A;
		if(A[2]){
			if(A[0] == 'E' && A[1] == 'O' && A[2] == 'F')break;
		}
		cin >> B;
		int ans = 0,p;
		for(int i = 0;A[i];i++){
			for(int j = 0;B[j];j++){
				if(A[i] == B[j]){
					for(p = 0;A[p+i] == B[p+j] and A[p+i];p++){}
					if(ans < p){
						ans = p;
					}
				}
			}
		}
		cout << ans;
	}
}

C++: #include <bits/stdc++.h>
#define FOR(i,n) for(int i=0;i<(int)(n);i++)
#define FORR(i,m,n) for(int i=(int)(m);i<(int)(n);i++)
#define pb(a) push_back(a)
#define ZERO(a) memset(a,0,sizeof(a))
#define len(a) sizeof(a)
#define ll long long
#define INF 1<<29
#define MAX 4111
using namespace std;

int dp[MAX][MAX];

void solve(){
 string s,t;
 while(scanf("%s",&s)){
  ZERO(dp);
  scanf("%s",&t);
  FOR(i,s.size()){
   FOR(j,t.size()){
    if(s[i]==t[j]){
     dp[i+1][j+1]=max(dp[i+1][j+1],dp[i][j]+1);
    }
   }
  }
  int ma=0;
  FOR(i,s.size()+1){
   FOR(j,t.size()+1){
    ma=max(ma,dp[i][j]);
   }
  }
  printf("%d",ma);
 }
}

int main(){
 solve();
 return 0;
}

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

int main(){
	string str1, str2;
	while(cin >> str1 >> str2){
		int count = 0;
		for(int i = 0; i < str1.size(); i++){
			for(int j = 0; j < str2.size(); j++){
				int k = 0;
				while(str1[i+k] == str2[j+k]){
					if(i + k > str1.size()-1 || j + k > str2.size()-1) break;
					count = max(count, k+1);
					k++;
					//cout << str2.substr(i, k) << endl;
				}
			}
		}
		cout << count << endl;
	}
}

C++: #include <bits/stdc++.h>
using namespace std;
#define Rep(i,N) for(int i = 0; i < N; i++)

int main()
{
  string S, W;
  int dp[4005] = {0};
  int maxv = 0;
  
  while(cin >> S >> W){

    Rep(i,W.size()) {
      for(int j = S.size(); j > 0; j--) {
        if(S[j - 1] == W[i]) {
          dp[j] = dp[j - 1] + 1;
	  maxv = max(maxv, dp[j]);
        } else dp[j] = 0;
      }
    }
  }
  cout << maxv << endl;
  return 0;
}