Submission #99322

#	Time	Username	Problem	Language	Result	Execution time	Memory
99322		TadijaSebez	Arranging Tickets (JOI17_arranging_tickets)	C++11	100 / 100	2087 ms	15860 KiB

arranging_tickets

#include <bits/stdc++.h>
using namespace std;
#define ll long long
const int N=200050;
int n,m,a[N],b[N],c[N];
int heap[N],tsz;
void Push(int x)
{
	heap[++tsz]=x;
	for(int i=tsz;i>1 && b[heap[i]]>b[heap[i>>1]];i>>=1) swap(heap[i],heap[i>>1]);
}
void Pop()
{
	heap[1]=heap[tsz--];
	for(int i=1,j;i*2<=tsz;i=j)
	{
		j=i*2;
		if(j!=tsz && b[heap[j+1]]>b[heap[j]]) j++;
		if(b[heap[j]]>b[heap[i]]) swap(heap[i],heap[j]);
		else break;
	}
}
ll sum[N],need[N],add[N],ost[N];
vector<int> ids[N];
bool Check(ll mid, int pos, ll flip)
{
	for(int i=1;i<=n;i++) add[i]=0;
	for(int i=1;i<pos;i++) need[i]=(sum[i]+flip-mid+1)/2;
	need[pos]=flip;
	tsz=0;
	ll done=0;
	for(int i=1;i<=pos;i++)
	{
		for(int j:ids[i]) if(a[j]<=pos && pos<b[j]) Push(j),ost[j]=c[j];
		while(tsz && done<need[i])
		{
			int j=heap[1];
			ll work=min(ost[j],need[i]-done);
			done+=work;
			ost[j]-=work;
			add[1]+=work;
			add[a[j]]-=2*work;
			add[b[j]]+=2*work;
			if(!ost[j]) Pop();
		}
		if(done<need[i]) return 0;
	}
	for(int i=1;i<=n;i++)
	{
		add[i]+=add[i-1];
		if(add[i]+sum[i]>mid) return 0;
	}
	return 1;
}
int main()
{
	scanf("%i %i",&n,&m);
	for(int i=1;i<=m;i++)
	{
		scanf("%i %i %i",&a[i],&b[i],&c[i]);
		if(a[i]>b[i]) swap(a[i],b[i]);
		sum[a[i]]+=c[i];
		sum[b[i]]-=c[i];
		ids[a[i]].push_back(i);
	}
	int fir=0,las=0;
	for(int i=1;i<=n;i++)
	{
		sum[i]+=sum[i-1];
		if(sum[i]>sum[fir]) fir=i;
		if(sum[i]==sum[fir]) las=i;
	}
	ll top=sum[fir],bot=0,mid,ans=top;
	while(top>=bot)
	{
		mid=top+bot>>1;
		if(Check(mid,fir,sum[fir]-mid)||Check(mid,fir,sum[fir]-mid+1)
		 ||Check(mid,las,sum[las]-mid)||Check(mid,las,sum[las]-mid+1)) ans=mid,top=mid-1;
		else bot=mid+1;
	}
	printf("%lld\n",ans);
	return 0;
}

Compilation message (stderr)

arranging_tickets.cpp: In function 'int main()':
arranging_tickets.cpp:57:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%i %i",&n,&m);
  ~~~~~^~~~~~~~~~~~~~~
arranging_tickets.cpp:60:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%i %i %i",&a[i],&b[i],&c[i]);
   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 35 / 35
• Subtask 3: 20 / 20
• Subtask 4: 20 / 20
• Subtask 5: 15 / 15