Submission #163214

#	Time	Username	Problem	Language	Result	Execution time	Memory
163214		TadijaSebez	허수아비 (JOI14_scarecrows)	C++11	100 / 100	1875 ms	9452 KiB

scarecrows

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
const int N=200050;
const int S=447;
const int H=N/S+1;
int SEQ[H][S],a[N],ptr[H];
bool use[N+S];
void Build(int B)
{
	int l=B*S,r=(B+1)*S-1;
	ptr[B]=0;
	for(int i=r;i>=l;i--) if(use[i])
	{
		while(ptr[B] && SEQ[B][ptr[B]-1]>a[i]) ptr[B]--;
		SEQ[B][ptr[B]++]=a[i];
	}
}
void Add(int pos)
{
	use[pos]=1;
	int B=pos/S;
	Build(B);
}
int x[N],y[N],id[N],stk[N],top;
vector<int> xs;
int main()
{
	int n;
	scanf("%i",&n);
	for(int i=1;i<=n;i++) scanf("%i %i",&x[i],&y[i]),xs.pb(x[i]);
	sort(xs.begin(),xs.end());
	for(int i=1;i<=n;i++) a[x[i]=lower_bound(xs.begin(),xs.end(),x[i])-xs.begin()+1]=y[i],id[i]=i;
	sort(id+1,id+1+n,[&](int i, int j){ return y[i]>y[j];});
	ll sol=0;
	for(int j=1,i;i=id[j],j<=n;j++)
	{
		int pos=x[i];
		int B=pos/S;
		int r=(B+1)*S-1;
		top=0;
		for(int k=r;k>pos;k--) if(use[k])
		{
			while(top && stk[top]>a[k]) top--;
			stk[++top]=a[k];
		}
		int mn=top?stk[1]:1e9+7;
		int ans=0;
		ans+=top;
		for(int k=B+1;k*S<=n;k++)
		{
			if(ptr[k])
			{
				ans+=upper_bound(SEQ[k],SEQ[k]+ptr[k],mn)-SEQ[k];
				mn=min(mn,SEQ[k][0]);
			}
		}
		sol+=ans;
		Add(x[i]);
	}
	printf("%lld\n",sol);
	return 0;
}

Compilation message (stderr)

scarecrows.cpp: In function 'int main()':
scarecrows.cpp:31:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%i",&n);
  ~~~~~^~~~~~~~~
scarecrows.cpp:32:50: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  for(int i=1;i<=n;i++) scanf("%i %i",&x[i],&y[i]),xs.pb(x[i]);
                        ~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 85 / 85