Submission #113364

#	Time	Username	Problem	Language	Result	Execution time	Memory
113364		TadijaSebez	Shortcut (IOI16_shortcut)	C++11	100 / 100	1291 ms	32504 KiB

shortcut

#include "shortcut.h"
#include <bits/stdc++.h>
using namespace std;
#define ll long long
const int N=1000050;
const ll inf=5e18;
int n,d[N],c,q[N],ql,qr;
ll x[N];
bool Check(ll k)
{
	ll mx=-inf,mn=inf;
	ll ls=-inf,rs=inf,ld=-inf,rd=inf;
	ql=1;qr=0;
	for(int i=1;i<=n;i++)
	{
		for(;ql<=qr && x[q[ql]]-d[q[ql]]<x[i]+d[i]-k;ql++) mx=max(mx,x[q[ql]]+d[q[ql]]),mn=min(mn,x[q[ql]]-d[q[ql]]);
        ls=max(ls,mx+x[i]+d[i]-k+c);
        rs=min(rs,mn+x[i]-d[i]+k-c);
        ld=max(ld,mx-x[i]+d[i]-k+c);
        rd=min(rd,mn-x[i]-d[i]+k-c);
        for(;ql<=qr && x[q[qr]]-d[q[qr]]>=x[i]-d[i];qr--);
        q[++qr]=i;
	}
	int l1=n+1,r1=n+1,l2=0,r2=0;
	for(int i=1;i<=n;i++)
	{
		for(;l1>=2 && x[i]+x[l1-1]>=ls;l1--);
		for(;r1>=1 && x[i]+x[r1]>rs;r1--);
		for(;l2<=n && x[i]-x[l2]>rd;l2++);
		for(;r2<n && x[i]-x[r2+1]>=ld;r2++);
		int l=max(l1,l2),r=min(r1,r2);
		if(l<=r) return 1;
	}
	return 0;
}
ll find_shortcut(int n, vector<int> l, vector<int> d, int c)
{
	::n=n;::c=c;::d[1]=d[0];int mxd=d[0];x[n+1]=inf;
    for(int i=2;i<=n;i++) x[i]=x[i-1]+l[i-2],::d[i]=d[i-1],mxd=max(mxd,d[i-1]);
	ll lo=0,hi=2*mxd+x[n],mi=lo+hi+1>>1;
	for(;lo<hi;mi=lo+hi+1>>1)
	{
		if(Check(mi)) hi=mi-1;
		else lo=mi;
	}
	return lo+1;
}

Compilation message (stderr)

shortcut.cpp: In function 'long long int find_shortcut(int, std::vector<int>, std::vector<int>, int)':
shortcut.cpp:40:32: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  ll lo=0,hi=2*mxd+x[n],mi=lo+hi+1>>1;
                           ~~~~~^~
shortcut.cpp:41:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  for(;lo<hi;mi=lo+hi+1>>1)
                ~~~~~^~

• Subtask 1: 9 / 9
• Subtask 2: 14 / 14
• Subtask 3: 8 / 8
• Subtask 4: 7 / 7
• Subtask 5: 33 / 33
• Subtask 6: 22 / 22
• Subtask 7: 4 / 4
• Subtask 8: 3 / 3