Submission #3195699

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define P pair<ll,ll>
#define FOR(I,A,B) for(ll I = (A); I < (B); ++I)
#define FORR(I,A,B) for(ll I = (B-1); I >= (A); --I)
#define SORT(x) (sort(x.begin(),x.end())) // 0 2 2 3 4 5 8 9
#define REV(x) (reverse(x.begin(),x.end())) //reverse
ll gcd(ll a,ll b){if(a<b)swap(a,b);if(a%b==0)return b;else return gcd(b,a%b);}
ll lcm(ll a,ll b){ll c=gcd(a,b);return ((a/c)*(b/c)*c);}//saisyo kobaisu
#define NEXTP(x) next_permutation(x.begin(),x.end())
const ll INF=1e18+7;
const ll MOD=1e9+7;

class BIT{
public:
	vector<int> bit;
	int M;
	// 1-index
	BIT(int M):
		bit(vector<int>(M+1, 0)), M(M) {}

	int sum(int i) {
		if (!i) return 0;
		return bit[i] + sum(i-(i&-i));
	}

	void add(int i, int x) {
		if (i > M) return;
		bit[i] += x;
		add(i+(i&-i), x);
	}
};


int main(){
	ios::sync_with_stdio(false);
	cin.tie(0);
	ll N,ans=1;
	cin >> N;
	ll p;cin>>p;
	BIT animal(N);
	animal.add(0+1,1);
	FOR(i,1,N){
		ll k;
		cin >> k;
		if((animal.sum(i)-animal.sum(i-k))==0){
			ans++;
			animal.add(i+1,1);
		}
	}
	cout << ans << endl;
}

Submission Info

Judge Result