Submission #133605

#	Time	Username	Problem	Language	Result	Execution time	Memory
133605		ckodser	Horses (IOI15_horses)	C++14	100 / 100	862 ms	49256 KiB

horses

#include "horses.h"
#include<bits/stdc++.h>

#define ll long long 
#define pb push_back
#define ld long double
#define mp make_pair
#define F first
#define S second
#define pii pair<ll,ll> 

using namespace :: std;

const ll maxn=5e5+500;
const ll inf=1e9+6;
const ll mod=1e9+7;

ll modizarb(long long a,long long b){return (a*b)%mod;}


ll y[maxn];
ll seg[maxn*4];
void bild(ll l,ll r,ll node){
    if(l+1==r){
	seg[node]=y[l];
	return;
    }
    ll mid=(l+r)/2;
    bild(l,mid,2*node);
    bild(mid,r,2*node+1);
    seg[node]=max(seg[2*node],seg[2*node+1]);
}
void update(ll l,ll r,ll node,ll pos){
    if(l+1==r){
	seg[node]=y[l];
	return;
    }
    ll mid=(l+r)/2;
    if(pos<mid)
	update(l,mid,2*node,pos);
    else 
	update(mid,r,2*node+1,pos);
    seg[node]=max(seg[2*node],seg[2*node+1]);
}
ll findMx(ll l,ll r,ll L,ll R,ll node){
    if(l<=L && R<=r){
	return seg[node];
    }
    if(r<=L || R<=l){
	return 0;
    }	
    ll mid=(L+R)/2;
    return max(findMx(l,r,L,mid,2*node),findMx(l,r,mid,R,2*node+1));
}
set<ll> st;
ll x[maxn];
ll rx[maxn];
ll n,Z;

ll poww(ll a,ll b){
    ll ans=1;
    while(b){
	if(b&1){
	    ans=(ans*a)%mod;
	}
	b>>=1;
	a=(a*a)%mod;
    }
    return ans;
}
ll findAns(){
    auto it=st.end();
    ll last=n;
    ll ans=0;
    ll t=Z;
    bool br=0;
    while(it!=st.begin()){
	it--;
	ll v=(*it);
	ll yy=findMx(v,last,0,n,1);
	ans=max(ans,yy);
	if(ans*x[v]>inf){
	    br=1;
	    break;
	}
	ans*=x[v];
	t=modizarb(t,rx[v]);
	last=v;
    }
    if(!br){
	ll v=0;
	ll yy=findMx(v,last,0,n,1);
	ans=max(ans,yy);
    }
    return modizarb(ans,t);
}
int init(int N, int X[], int Y[]){
    n=N;
    Z=1;
    for(ll i=0;i<n;i++){
	x[i]=X[i];
	Z=modizarb(Z,X[i]);
	rx[i]=poww(x[i],mod-2);
	y[i]=Y[i];
	if(x[i]!=1)st.insert(i);
    }
    bild(0,n,1);
    return findAns();
}
int updateX(int pos, int val) {	
    Z=modizarb(Z,rx[pos]);
    if(x[pos]!=1 && val==1){
	st.erase(pos);
    }
    if(x[pos]==1 && val!=1){
	st.insert(pos);
    }
    x[pos]=val;
    Z=modizarb(Z,val);
    rx[pos]=poww(x[pos],mod-2);
    return findAns();
}
int updateY(int pos, int val){
    y[pos]=val;
    update(0,n,1,pos);
    return findAns();
}

Compilation message (stderr)

horses.cpp: In function 'int init(int, int*, int*)':
horses.cpp:108:19: warning: conversion to 'int' from 'long long int' may alter its value [-Wconversion]
     return findAns();
            ~~~~~~~^~
horses.cpp: In function 'int updateX(int, int)':
horses.cpp:121:19: warning: conversion to 'int' from 'long long int' may alter its value [-Wconversion]
     return findAns();
            ~~~~~~~^~
horses.cpp: In function 'int updateY(int, int)':
horses.cpp:126:19: warning: conversion to 'int' from 'long long int' may alter its value [-Wconversion]
     return findAns();
            ~~~~~~~^~

• Subtask 1: 17 / 17
• Subtask 2: 17 / 17
• Subtask 3: 20 / 20
• Subtask 4: 23 / 23
• Subtask 5: 23 / 23