Submission #154841

#	Time	Username	Problem	Language	Result	Execution time	Memory
154841		junodeveloper	Horses (IOI15_horses)	C++14	100 / 100	569 ms	49436 KiB

horses

#include "horses.h"
#include <bits/stdc++.h>
using namespace std;
 
typedef long long ll;
 
const int off=1<<19;
const int mod=1e9+7;
 
struct MULT {
	int tree[off<<1];
	MULT() {memset(tree,0,sizeof(tree));}
	void update(int p,int x) {
		p+=off;
		tree[p]=x;p/=2;
		while(p>0) {
			tree[p]=(ll)tree[p<<1]*tree[p<<1|1]%mod;
			p>>=1;
		}
	}
	int query(int l,int r) {
		int ret=1;
		l+=off,r+=off;
		while(l<r) {
			if(l%2==1) ret=(ll)ret*tree[l++]%mod;
			if(r%2==0) ret=(ll)ret*tree[r--]%mod;
			l>>=1,r>>=1;
		}
		if(l==r) ret=(ll)ret*tree[l]%mod;
		return ret;
	}
} mult;
 
struct MAXT {
	int tree[off<<1];
	MAXT() {memset(tree,0,sizeof(tree));}
	void update(int p,int x) {
		p+=off;
		tree[p]=x;p/=2;
		while(p>0) {
			tree[p]=max(tree[p<<1],tree[p<<1|1]);
			p>>=1;
		}
	}
	int query(int l,int r) {
		int ret=0;
		l+=off,r+=off;
		while(l<r) {
			if(l%2==1) ret=max(ret,tree[l++]);
			if(r%2==0) ret=max(ret,tree[r--]);
			l>>=1,r>>=1;
		}
		if(l==r) ret=max(ret,tree[l]);
		return ret;
	}
} maxt;
 
int n;
int *x, *y;
set<int> st;
 
int solve() {
	auto it=st.end(); it--;
	int i,j; ll r=1;
	while(it!=st.begin()) {
		r*=x[*it];
		if(r>(ll)1e9) break;
		it--;
	}
	int fir=*it;
	r=1; ll mx=0;
	while(it!=st.end()) {
		i=*it;
		if(next(it)==st.end()) j=n-1;
		else j=*next(it)-1;
		mx=max(mx,(ll)r*maxt.query(i,j));it++;
		if(it!=st.end()) r*=x[*it];
	}
	mx%=mod;
	return (ll)mult.query(0,fir)*mx%mod;
}
 
int init(int N, int X[], int Y[]) {
	n=N;
	x=X,y=Y;
	int i;
	for(i=0;i<n;i++) {
		mult.update(i,x[i]);
		maxt.update(i,y[i]);
		if(x[i]!=1) st.insert(i);
	}
	st.insert(0);
	return solve();
}
 
int updateX(int pos, int val) {
	if(pos&&x[pos]!=1) {
		st.erase(pos);
	}
	x[pos]=val;
	if(pos&&x[pos]!=1) {
		st.insert(pos);
	}
	mult.update(pos,val);
	return solve();
}
 
int updateY(int pos, int val) {
	y[pos]=val;
	maxt.update(pos,val);
	return solve();
}

Compilation message (stderr)

horses.cpp: In member function 'void MULT::update(int, int)':
horses.cpp:17:39: warning: conversion to 'int' from 'll {aka long long int}' may alter its value [-Wconversion]
    tree[p]=(ll)tree[p<<1]*tree[p<<1|1]%mod;
            ~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~
horses.cpp: In member function 'int MULT::query(int, int)':
horses.cpp:25:36: warning: conversion to 'int' from 'll {aka long long int}' may alter its value [-Wconversion]
    if(l%2==1) ret=(ll)ret*tree[l++]%mod;
                   ~~~~~~~~~~~~~~~~~^~~~
horses.cpp:26:36: warning: conversion to 'int' from 'll {aka long long int}' may alter its value [-Wconversion]
    if(r%2==0) ret=(ll)ret*tree[r--]%mod;
                   ~~~~~~~~~~~~~~~~~^~~~
horses.cpp:29:31: warning: conversion to 'int' from 'll {aka long long int}' may alter its value [-Wconversion]
   if(l==r) ret=(ll)ret*tree[l]%mod;
                ~~~~~~~~~~~~~~~^~~~
horses.cpp: In function 'int solve()':
horses.cpp:80:33: warning: conversion to 'int' from 'll {aka long long int}' may alter its value [-Wconversion]
  return (ll)mult.query(0,fir)*mx%mod;
         ~~~~~~~~~~~~~~~~~~~~~~~~^~~~

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