Submission #1613031

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Source Code Expand

#include <bits/stdc++.h>
#define REP(i,a,b) for(int i=(a);i<(b);i++)
#define RREP(i,a,b) for(int i=(a);i>=(b);i--)
typedef long long ll; typedef long double ld;
using namespace std;
const int INF=1e9, MOD=1e9+7;
const int MAX_N=10000;
int n,k,a[100010]={},li[100010][3]={};

int main(){
	cin >> n >> k;
	REP(i,0,k) cin >> a[i];
	sort(a,a+k);
	int ma=0,c=1,cou=0;
	if(a[0]){
		REP(i,0,k){
			if(a[i]+1==a[i+1]){
				c++;
			}else{
				ma=max(ma,c);
				c=1;
			}
		}
	}else{
		li[0][0]=a[1];
		REP(i,1,k){
			if(a[i]+1==a[i+1]){
				c++;
			}else{
				li[cou][1]=a[i];
				li[cou+1][0]=a[i+1];
				li[cou][2]=c;
				cou++; c=1;
			}
		}
		
		REP(i,0,n){
			if(li[i][1]+2==li[i+1][0]){
				ma=max(ma,li[i][2]+li[i+1][2]+1);
			}
		}
	}
		
	cout << ma << endl;
	return 0;
}

Submission Info

Judge Result