Submission #200542

#	Time	Username	Problem	Language	Result	Execution time	Memory
200542		a1_N	Bigger segments (IZhO19_segments)	C++17	37 / 100	1593 ms	148932 KiB

segments

#include <bits/stdc++.h>

#define F first
#define S second

using namespace std;

const int N = 5e5 + 5;
const long long M = (long long)1e15;

int n,a[N];

long long pref[N];

pair<int,long long> dp[N];

unordered_map< long long,pair<int,long long> > t;

void upd(long long pos,pair<long long,long long> val,long long v = 1,long long tl = 1,long long tr = M){
	if(tl == tr){
		t[v] = val;
		return;
	}	
	long long tm = (tl + tr) >> 1;
	if(pos <= tm) upd(pos,val,v << 1,tl,tm);
	else upd(pos,val,v << 1 | 1,tm + 1,tr);
	t[v] = max(t[v << 1],t[v << 1 | 1]);
}

pair<int,long long> get(long long l,long long r,long long v = 1,long long tl = 1,long long tr = M){
	if(l <= tl && tr <= r) return t[v];
	if(tl > r || tr < l) return make_pair(0,0);
	long long tm = (tl + tr) >> 1;
	return max(get(l,r,v << 1,tl,tm),get(l,r,v << 1 | 1,tm + 1,tr));
} 

int main(){
	//ios_base::sync_with_stdio(0),cin.tie(0),cout.tie(0);
	scanf("%d",&n);
	for(int i = 1; i <= n; i++){
		scanf("%d",&a[i]);
		pref[i] = pref[i - 1] + a[i];
	}
	dp[1] = make_pair(1,a[1]);
	upd(pref[1] + dp[1].S,make_pair(dp[1].F,1));
	for(int i = 2; i <= n; i++){
		dp[i] = make_pair(dp[i - 1].F,dp[i - 1].S + a[i]);
		pair<int,long long> cur = get(1,pref[i]);
		if(cur.F > 0) dp[i] = make_pair(cur.F + 1,pref[i] - pref[cur.S]);
		upd(pref[i] + dp[i].S,make_pair(dp[i].F,i));	
	}
	printf("%d",dp[n].F);
	return 0;
}

Compilation message (stderr)

segments.cpp: In function 'int main()':
segments.cpp:39:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&n);
  ~~~~~^~~~~~~~~
segments.cpp:41:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d",&a[i]);
   ~~~~~^~~~~~~~~~~~

• Subtask 1: 13 / 13
• Subtask 2: 14 / 14
• Subtask 3: 10 / 10
• Subtask 4: 0 / 36
• Subtask 5: 0 / 27