Submission #795796

#	Time	Username	Problem	Language	Result	Execution time	Memory
795796		Username4132	Horses (IOI15_horses)	C++14	0 / 100	1543 ms	31828 KiB

horses

#include "horses.h"
#include<iostream>
#include<vector>
#include<algorithm>
#include<set>
using namespace std;
using ll = long long;
using pii = pair<int, int>;
using pli = pair<ll, int>;
#define forn(i, n) for(int i=0; i<(int)n; ++i)
#define forsn(i, s, n) for(int i=s; i<(int)n; ++i)
#define PB push_back
#define F first
#define S second

const int MAXN = 500010, MOD = 1000000007;
int n, arr[MAXN], brr[MAXN];
set<int> ones;

pii query(int l, int r){
	//cerr << l << ' ' << r << endl;
	pii mx={0, -1};
	forsn(i, l, r) mx=max(mx, {brr[i], i});
	return mx;
}

int pro(int r){
	ll ret=1;
	forn(i, r+1) ret=(ret*arr[i])%MOD;
	return (ret*brr[r])%MOD;
}


int solve(){
	ll prod=1;
	vector<int> lis;
	int sz = ones.size(), pos = n-1;

	auto itr = ones.end();
	forn(i, sz){
		itr = prev(itr);
		prod*=arr[*itr];
		lis.PB(*itr);
		if(prod>1000000000) break;
	}
	reverse(lis.begin(), lis.end());

	ll p=1;
	pli mx = {0, 0};
	for(int el:lis){
		if(el!=lis.back()) p*=arr[el];
		pli opt = query(el, n);
		opt.F*=p;
		mx = max(mx, opt);
	}
	pli aa = query(0, n);
	if(lis.empty() || ((aa.F / mx.F) >= arr[lis.back()])) mx=aa;
	return pro(mx.S);
}

int init(int N, int X[], int Y[]) {
	n=N;
	forn(i, n){
		arr[i]=X[i];
		if(arr[i]!=1) ones.insert(i);
	}
	forn(i, n) brr[i]=Y[i];
	return solve();
}

int updateX(int pos, int val) {	
	if(arr[pos]==1 && val!=1) ones.insert(pos);
	if(arr[pos]!=1 && val==1) ones.erase(pos);
	arr[pos]=val;
	return solve();
}

int updateY(int pos, int val) {
	brr[pos]=val;
	return solve();
}

Compilation message (stderr)

horses.cpp: In function 'int pro(int)':
horses.cpp:30:21: warning: conversion from 'll' {aka 'long long int'} to 'int' may change value [-Wconversion]
   30 |  return (ret*brr[r])%MOD;
      |         ~~~~~~~~~~~~^~~~
horses.cpp: In function 'int solve()':
horses.cpp:37:20: warning: conversion from 'std::set<int>::size_type' {aka 'long unsigned int'} to 'int' may change value [-Wconversion]
   37 |  int sz = ones.size(), pos = n-1;
      |           ~~~~~~~~~^~
horses.cpp:37:24: warning: unused variable 'pos' [-Wunused-variable]
   37 |  int sz = ones.size(), pos = n-1;
      |                        ^~~

• Subtask 1: 0 / 17
• Subtask 2: 0 / 17
• Subtask 3: 0 / 20
• Subtask 4: 0 / 23
• Subtask 5: 0 / 23