Submission #201337

#	Time	Username	Problem	Language	Result	Execution time	Memory
201337		guangxuan	Bigger segments (IZhO19_segments)	C++14	73 / 100	1574 ms	142052 KiB

segments

#include <bits/stdc++.h>

using namespace std;

int a[500009];
long long rs[500009];
pair<int,long long> dp[500009];
unordered_map<long long,pair<int,long long> >fw;

pair<int,long long> query(long long x){
	pair<int,long long> ans = {-1,-1};
	for(x++;x;x-=x&(-x)){
		if(fw.find(x)==fw.end())continue;
		ans = max(ans,fw[x]);
	}
	return ans;
}

void up(long long x,pair<int,long long> v ){
	for(x++;x<1e15;x+=x&(-x)){
		if(fw.find(x)==fw.end())fw[x] = v;
		else fw[x] = max(fw[x],v);
	}
}

int main(){
	int n;
	scanf("%d",&n);
	for(int i=0;i<n;i++){
		scanf("%d",&a[i]);
		rs[i+1]=rs[i]+a[i];
	}
	up(0,{0,0});
	for(int i=1;i<=n;i++){
		pair<int,long long> res = query(rs[i]); 
		dp[i] = {res.first,res.second - rs[i]};
		dp[i].first++;
		up(rs[i] - dp[i].second,{dp[i].first,rs[i]});
		//cout << dp[i].first << ' ' << dp[i].second << '\n';
		// cout << res.first << ' ' << res.second.first << ' ' << res.second.second << '\n';
	}
	printf("%d", dp[n].first);
}

Compilation message (stderr)

segments.cpp: In function 'int main()':
segments.cpp:28:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&n);
  ~~~~~^~~~~~~~~
segments.cpp:30:8: 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: 36 / 36
• Subtask 5: 0 / 27