Submission #201369

#	Time	Username	Problem	Language	Result	Execution time	Memory
201369		guangxuan	Bigger segments (IZhO19_segments)	C++14	73 / 100	627 ms	262148 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;

struct node{
	long long s,e,m;
	pair<int,long long> v;
	node *l,*r;
	node(long long _s,long long _e):s(_s),e(_e),m((_s+_e)/2),v({-1,-1}),l(NULL),r(NULL){}
	void up(long long x,pair<int,long long> uv){
		if(s==e){
			v = max(v,uv);return;
		}
		if(x>m){
			if(r==NULL)r = new node(m+1,e);
			r->up(x,uv);
		}
		else{
			if(l==NULL)l = new node(s,m);
			l->up(x,uv);
		}
		v = {-1,-1};
		if(r)v = max(v,r->v);
		if(l)v = max(v,l->v);
	}
	pair<int,long long> qu(long long x,long long y){
		if(s==x&&e==y)return v;
		if(x>m){
			if(r)return r->qu(x,y);
			else return {-1,-1};
		}
		if(y<=m){
			if(l)return l->qu(x,y);
			else return {-1,-1};
		}
		pair<int,long long> qv = {-1,-1};
		if(r)qv = max(qv,r->qu(m+1,y));
		if(l)qv = max(qv,l->qu(x,m));
		return qv;
	}
}*root;

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];
	}
	root = new node(0,(long long)1e15);
	root->up(0,{0,0});
	for(int i=1;i<=n;i++){
		pair<int,long long> res = root->qu(0,rs[i]); 
		dp[i] = {res.first,res.second - rs[i]};
		dp[i].first++;
		root->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:66:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&n);
  ~~~~~^~~~~~~~~
segments.cpp:68:8: 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