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<iostream>
#include<string.h>
using namespace std;

char A[4002],B[4002];
short int length[4000][4000];
int mmax[200],mcor = 0;
int main(){
	int i,j,lenA,lenB;
	while(cin >> A[0]){
		cin >> A+1;
		cin >> B;
		lenA = strlen(A)-1;
		lenB = strlen(B)-1;
		for(i = 0;i < lenA;i++){
			for(j = 0;j < lenB;j++){
				length[i][j] = -1;
			}
		}
		for(i = 0;i < lenA;i++){
			for(j = 0;j < lenB;j++){
				if(length[i][j] >= 0)continue;
				for(int k = 0;i+k < lenA && i+k < lenB;k++){
						if(A[i+k] != B[i+k]){
							length[i][j] = k;
							break;
						}
				}
			}
		}
		for(i = 0;i < lenA;i++){
			for(j = 0;j < lenB;j++){
				if(mmax[mcor] < length[i][j])
					mmax[mcor] = length[i][j];
			}
		}
		mcor++;
	}
	for(i = 0;i < mcor;i++){
		cout << mmax[i] << endl;
	}
	return 0;
}

C++: #include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <cmath>
#include <cstdio>
#include <functional>
#include <numeric>
#include <stack>
#include <queue>
#include <map>
#include <set>
#include <utility>
#include <sstream>
#include <complex>
#include <fstream>

using namespace std;

#define FOR(i,a,b) for(long long i=(a);i<(b);i++)
#define REP(i,N) for(long long i=0;i<(N);i++)
#define ALL(s) (s).begin(),(s).end()
#define fi first
#define se second

#define PI acos(-1.0)
#define INF 10e9+9
#define EPS 1e-10
#define MAX_N 100100
#define MAX_M 100100

typedef long long ll;
typedef pair<ll, ll> P;
typedef pair<double, double> PD;
typedef pair<string, ll> PS;
typedef vector<ll> V;
typedef pair<P, char> PC;

string s, t;
int dp[10000][10000];

int main(){
	int MAX = -1;
	cin >> s >> t;
	REP(i, s.size()){
		REP(j, t.size()){
			if (s[i] == t[j]){
				dp[i + 1][j + 1] = dp[i][j] + 1;
			}
			MAX = max(MAX, dp[i + 1][j + 1]);
		}
	}
	cout << MAX << endl;
}

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

typedef long long ll;
typedef pair<int,int> pii;
typedef pair<ll,int> plli;
typedef pair<int,pii> pipii;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<vi> vvi;
typedef vector<vvi> vvvi;
typedef vector<pii> vpii;

#define rep(i,n) for (int i=0;i<(n);i++)
#define rep2(i,a,b) for (int i=(a);i<(b);i++)
#define rrep(i,n) for (int i=(n);i>0;i--)
#define rrep2(i,a,b) for (int i=(a);i>b;i--)
#define pb push_back
#define fi first
#define se second
#define all(a) (a).begin(),(a).end()

const ll mod = 1e9 + 7;
const ll INF = 1<<30;
const int dx4[4] = {1, 0, -1, 0};
const int dy4[4] = {0, 1, 0, -1};
const int dx8[8] = {1, 1, 1, 0, 0, -1, -1, -1};
const int dy8[8] = {0, 1, -1, 1, -1, 0, 1, -1};
const double pi = 3.141592653589793;


signed main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    string s, t;
    while (cin >> s >> t) {
        int ssize = s.length();
        int tsize = t.length();
        vector<vector<string>> ss(ssize + 1), tt(tsize + 1);
        rep(i, ssize)rep(j, ssize - i + 1) ss[j].pb(s.substr(i, j));
        rep(i, tsize)rep(j, tsize - i + 1) tt[j].pb(t.substr(i, j));
        int low = 0;
        int high = max(ssize, tsize) + 1;
        while (high - low > 1) {
            int mid = (high + low) / 2;
            bool ok = false;
            if (mid > ssize || mid > tsize) {high = mid; continue;}
            rep(i, ss[mid].size())rep(j, tt[mid].size()) {
                if (ss[mid][i] == tt[mid][j]) {
                    ok = true;
                    break;
                }
            }
            if (ok) low = mid;
            else high = mid;
        }
        cout << low << endl;
    }
}

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

#define rep(i, n) for(int i = 0; i < (n); ++i)

using namespace std;

string s, t;
int dp[4001][4001];

int main(){
	while(cin >> s >> t){
		rep(i, s.size() + 1){
			dp[i][0] = 0;
		}
		rep(i, t.size() + 1){
			dp[0][i] = 0;
		}
		for(int i = 1; i <= s.size(); ++i){
			for(int j = 1; j <= t.size(); ++j){
				dp[i][j] = s[i - 1] == t[j - 1] ? dp[i - 1][j - 1] + 1 : 0;
			}
		}
		int ans = 0;
		rep(i, s.size()){
			ans = max(*max_element(dp[i], dp[i] + t.size() + 1), ans);
		}
		cout << ans << endl;
	}
	return 0;
}

C++: #include<iostream>
#include<string>
#include<cmath>
#include<queue>
#include<map>
#include<set>
#include<list>
#include<iomanip>
#include<vector>
#include<functional>
#include<algorithm>
#include<cstdio>
#include<unordered_map>
using namespace std;
typedef long long ll;
vector<int>v[26][2];
int main() {
	string a, b;
	while (cin >> a >> b) {
		for (int i = 0; i < 26; i++) {
			v[i][0].clear();
			v[i][1].clear();
		}
		for (int i = 0; i < a.length(); i++) {
			int k = (int)a[i] - 'A';
			v[k][0].push_back(i);
		}
		for (int i = 0; i < b.length(); i++) {
			int k = (int)b[i] - 'A';
			v[k][1].push_back(i);
		}
		int sum = 0;
		for (int i = 0; i < 26; i++) {
			for (int j = 0; j < v[i][0].size(); j++) {
				for (int x = 0; x < v[i][1].size(); x++) {
					int a2 = v[i][0][j], b2 = v[i][1][x];
					int sum2 = 0;
					while (a[a2] == b[b2]&&a2<a.length()&&b2<b.length()) {
						sum2++;
						a2++;
						b2++;
					}
					sum = max(sum, sum2);
				}
			}
		}
		cout << sum << endl;
	}
}

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

string s, t;
char tmp[4001];
int dp[4001][4001];

int main(){
	while(1){
		scanf("%s", tmp);
		if(tmp[0] == EOF) break;

		s = tmp;
		scanf("%s", tmp);
		t = tmp;

		for(int i=0; i<4001; i++)
			for(int j=0; j<4001; j++)
				dp[i][j] = 0;

		int ans = 0;
		for(int i=1; i<s.size(); i++){
			for(int j=1; j<t.size(); j++){
				if(s[i-1] == t[j-1]){
					dp[i][j] = dp[i-1][j-1]+1;
				}else{
					dp[i][j] = 0;
				}
				ans = max(ans, dp[i][j]);
			}
		}

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

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

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

C++: #include <iostream>
#include <string>
#include <algorithm>
using namespace std;
int main(){
	string a,b;
	while(cin>>a>>b){
		int n=0;
		int la=a.size();
		int lb=b.size();
		for(int i=1-la;i<lb;i++){
			int k=0;
			for(int j=0;j<la;j++){
				if(j+i<0||j+i>lb-1){
					k=0;
				}
				else if(a[j]==b[j+i]){
					k++;
					n=max(n,k);
				}
				else{
					k=0;
				}
			}
		}
		cout<<n<<endl;
	}
    return 0;
}

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

int cnt[4001][4001];

int main(){
	string a, b;
	int na, nb;

	cin >> a >> b;
	na = a.length();
	nb = b.length();

	for(int i=0; i<na+1; i++){
		cnt[i][0] = 0;
	}
	for(int j=0; j<nb+1; j++){
		cnt[0][j] = 0;
	}

	int mx = 0;
	for(int i=0; i<na; i++){
		for(int j=0; j<nb; j++){
			if(a[i]==b[j]){
				cnt[i+1][j+1] = cnt[i][j] + 1;
				if(mx < cnt[i+1][j+1]){
					mx = cnt[i+1][j+1];
				}
			}else{
				cnt[i+1][j+1] = 0;
			}
		}
	}
	cout << mx << endl;
	return 0;
}