Submission #1018582

#	Time	Username	Problem	Language	Result	Execution time	Memory
1018582		parsadox2	Horses (IOI15_horses)	C++17	17 / 100	221 ms	45908 KiB

horses

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

using namespace std;

const long long N = 5e5 + 10 , mod = 1e9 + 7;

long long n , x[N] , y[N] , mulx;
set <long long> st;

long long tav(long long a , long long b)
{
	long long res = 1;
	while(b)
	{
		if(b & 1)
			res = 1LL * res * a % mod;
		b >>= 1;
		a = 1LL * a * a % mod;
	}
	return res;
}

struct SEG{
	long long mx[N << 4];
	void Build(long long node = 1 , long long nl = 0 , long long nr = n)
	{
		if(nr - nl == 1)
		{
			mx[node] = y[nl];
			return;
		}
		long long mid = (nl + nr) >> 1 , lc = node << 1 , rc = lc | 1;
		Build(lc , nl , mid);  Build(rc , mid , nr);
		mx[node] = max(mx[lc] , mx[rc]);
	}
	void Update(long long id , long long node = 1 , long long nl = 0 , long long nr = n)
	{
		if(nr - nl == 1)
		{
			mx[node] = y[nl];
			return;
		}
		long long mid = (nl + nr) >> 1 , lc = node << 1 , rc = lc | 1;
		if(id < mid)
			Update(id , lc , nl , mid);
		else
			Update(id , rc , mid , nr);
		mx[node] = max(mx[lc] , mx[rc]);
	}
	long long Get(long long l , long long r , long long node = 1 , long long nl = 0 , long long nr = n)
	{
		if(r <= nl || nr <= l)
			return 0;
		if(l <= nl && nr <= r)
			return mx[node];
		long long mid = (nl + nr) >> 1 , lc = node << 1 , rc = lc | 1;
		return max(Get(l , r , lc , nl , mid) , Get(l , r , rc , mid , nr));
	}
} seg;

long long Solve2()
{
	long long tmpx = 1 , mx_x = 1 , mx_y = 1;
	for(int i = n - 1 ; i > -1 ; i--)
	{
		if(y[i] >= 1LL * mx_x * mx_y)
		{
			mx_y = y[i];
			mx_x = x[i];
		}
		else
		{
			mx_x *= x[i];
		}
		tmpx *= x[i];
		if(mx_x * mx_y > mod)
			break;
	}
	int res = 1LL * mx_x * mx_y % mod;
	return 1LL * mulx * tav(tmpx , mod - 2) % mod * res % mod;
}

long long Solve()
{
	long long tmpx = 1 , mx_x = 1 , mx_y = 1;
	for(auto asd : st)
	{
		auto u = abs(asd);
		long long Y = seg.Get(u , n);
		if(Y >= 1LL * mx_x * mx_y)
		{
			mx_y = Y;
			mx_x = x[u];
		}
		else
		{
			mx_x *= x[u];
		}
		tmpx *= x[u];
		if(1LL * mx_x * mx_y > mod)
			break;
	}
	long long res = 1LL * mx_x * mx_y % mod;
	if(seg.Get(0 , n) > 1LL * mx_x * mx_y)
		res = seg.Get(0 , n);
	return 1LL * mulx * tav(tmpx , mod - 2) % mod * res % mod;
}

int init(int nn, int X[], int Y[]) {
	mulx = 1;
	n = nn;
	for(long long i = 0 ; i < n ; i++)
	{
		x[i] = X[i];
		y[i] = Y[i];
		mulx = 1LL * mulx * x[i] % mod;
	}
	seg.Build();
	for(long long i = 0 ; i < n ; i++)  if(x[i] > 1)
		st.insert(-i);
	return Solve2();
}

int updateX(int pos, int val) {	
	if(x[pos] > 1)
		st.erase(-pos);
	mulx = 1LL * mulx * tav(x[pos] , mod - 2) % mod;
	x[pos] = val;
	if(x[pos] > 1)
		st.insert(-pos);
	mulx = 1LL * mulx * x[pos] % mod;
	return Solve2();
}

int updateY(int pos, int val) {
	y[pos] = val;
	seg.Update(pos);
	return Solve2();
}

Compilation message (stderr)

horses.cpp: In function 'long long int Solve2()':
horses.cpp:65:16: warning: conversion from 'long long int' to 'int' may change value [-Wconversion]
   65 |  for(int i = n - 1 ; i > -1 ; i--)
      |              ~~^~~
horses.cpp:80:30: warning: conversion from 'long long int' to 'int' may change value [-Wconversion]
   80 |  int res = 1LL * mx_x * mx_y % mod;
      |            ~~~~~~~~~~~~~~~~~~^~~~~
horses.cpp: In function 'int init(int, int*, int*)':
horses.cpp:122:15: warning: conversion from 'long long int' to 'int' may change value [-Wconversion]
  122 |  return Solve2();
      |         ~~~~~~^~
horses.cpp: In function 'int updateX(int, int)':
horses.cpp:133:15: warning: conversion from 'long long int' to 'int' may change value [-Wconversion]
  133 |  return Solve2();
      |         ~~~~~~^~
horses.cpp: In function 'int updateY(int, int)':
horses.cpp:139:15: warning: conversion from 'long long int' to 'int' may change value [-Wconversion]
  139 |  return Solve2();
      |         ~~~~~~^~

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