Submission #1042036

#	Time	Username	Problem	Language	Result	Execution time	Memory
1042036		fv3	Horses (IOI15_horses)	C++14	100 / 100	1049 ms	73808 KiB

horses

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

using namespace std;
typedef long long ll;

const ll mod = 1e9 + 7;
int N; vector<ll> X, Y;

int nt = 1;
vector<ll> st;
vector<ll> st_mod;
vector<ll> st_mx;

set<int> notOne;

int mx_index = 0;

ll get_range(int l, int r, int k, int x, int y)
{
	if (y < l || x > r) return 1;
	if (x >= l && y <= r) return st[k];
	int c = (x + y) / 2;
	return get_range(l, r, k*2, x, c) * get_range(l, r, k*2|1, c+1, y);
}

ll get_mod_range(int l, int r, int k, int x, int y)
{
	if (y < l || x > r) return 1;
	if (x >= l && y <= r) return st_mod[k];
	int c = (x + y) / 2;
	return (get_mod_range(l, r, k*2, x, c) * get_mod_range(l, r, k*2|1, c+1, y)) % mod;
}

ll get_max_range(int l, int r, int k, int x, int y)
{
	if (y < l || x > r) return 1;
	if (x >= l && y <= r) return st_mx[k];
	int c = (x + y) / 2;
	return max(get_max_range(l, r, k*2, x, c), get_max_range(l, r, k*2|1, c+1, y));	
}

int get_full_max()
{
	ll res = (X[0] * Y[0]) % mod, cnt = X[0];
	mx_index = 0;

	for (int i = 1; i < N; i++)
	{
		cnt = (cnt * X[i]) % mod;
		ll last_mult = Y[mx_index];

		ll mult_range = get_range(mx_index + 1, i, 1, 0, nt - 1); 

		if (mult_range >= last_mult || mult_range * Y[i] >= last_mult)
		{
			res = (cnt * Y[i]) % mod;
			mx_index = i;
		}
	}

	return (int)res;
}

int get_max()
{
	// Find the value of s
	// Go left 60 non-one steps
	int c = 0;
	int s = N - 1;
	while (s > 0 && c < 60)
	{
		c++;
		if (X[s] > 1)
		{
			s--;
			continue;
		}

		auto it = notOne.lower_bound(s);
		if (it == notOne.begin())
			s = 0;
		else
			s = *--it;
	}

	mx_index = s;
	ll cnt = get_mod_range(0, s, 1, 0, nt - 1);
	ll res, mx_1;
	if (X[s] == 1)
	{
		auto it = notOne.lower_bound(s);
		if (it == notOne.end())
			return (cnt * get_max_range(s, N - 1, 1, 0, nt - 1)) % mod;

		int r = *notOne.lower_bound(s); 
		mx_1 = get_max_range(s, r - 1, 1, 0, nt - 1);
		res = (cnt * mx_1) % mod;
		s = r;
	}
	else
	{
		res = (Y[s] * cnt) % mod;
		s++;
	}

	for (int i = s; i < N; )
	{
		ll last_mult = (X[mx_index] == 1 ? mx_1 : Y[mx_index]);
		ll mult_range = get_range(mx_index + 1, i, 1, 0, nt - 1); 
		if (X[i] == 1)
		{
			auto it = notOne.lower_bound(i); 
			int r;
			if (it == notOne.end())
				r = N;
			else
				r = *it;

			int mx_in_range = get_max_range(i, r-1, 1, 0, nt-1); 
			ll val =  Y[mx_in_range];

			if (mult_range * mx_in_range >= last_mult)
			{
				res = (cnt * mx_in_range) % mod;
				mx_index = i;
				mx_1 = mx_in_range;
			}

			i = r;
			continue;
		}

		cnt = (cnt * X[i]) % mod;
		if (mult_range >= last_mult || mult_range * Y[i] >= last_mult)
		{
			res = (cnt * Y[i]) % mod;
			mx_index = i;
		}
		i++;
	}

	return (int)res;
}

int init(int n, int x[], int y[]) 
{
	N = n;
	X.resize(N);
	Y.resize(N);

	for (int i = 0; i < N; i++)
	{
		X[i] = x[i];
		Y[i] = y[i];

		if (X[i] > 1)
			notOne.insert(i);
	}

	while (nt < N) nt <<= 1;
	st = st_mx = st_mod = vector<ll>(2 * nt, 1);
	for (int i = 0; i < N; i++)
	{
		st[nt + i] = X[i];
		st_mod[nt + i] = X[i];
		st_mx[nt + i] = Y[i];
	}
	for (int i = nt-1; i >= 1; i--)
	{
		st[i] = st[i*2] * st[i*2|1];
		st_mod[i] = (st_mod[i*2] * st_mod[i*2|1]) % mod;
		st_mx[i] = max(st_mx[i*2], st_mx[i*2|1]);
	}

	return get_full_max();
}

int updateX(int pos, int val) 
{
	if (X[pos] > 1)
		notOne.erase(pos);

	X[pos] = val;
	if (val > 1)
		notOne.insert(pos);

	pos += nt;
	st[pos] = val;
	st_mod[pos] = val;

	for (pos /= 2; pos >= 1; pos /= 2)
	{
		st[pos] = st[pos*2] * st[pos*2|1];
		st_mod[pos] = (st_mod[pos*2] * st_mod[pos*2|1]) % mod;
	}

	return get_max();
}

int updateY(int pos, int val) 
{
	Y[pos] = val;

	pos += nt;
	st_mx[pos] = val;

	for (pos /= 2; pos >= 1; pos /= 2)
	{
		st_mx[pos] = max(st_mx[pos*2], st_mx[pos*2|1]);
	}

	return get_max();
}

Compilation message (stderr)

horses.cpp: In function 'int get_max()':
horses.cpp:94:57: warning: conversion from 'll' {aka 'long long int'} to 'int' may change value [-Wconversion]
   94 |    return (cnt * get_max_range(s, N - 1, 1, 0, nt - 1)) % mod;
      |           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~
horses.cpp:120:35: warning: conversion from 'll' {aka 'long long int'} to 'int' may change value [-Wconversion]
  120 |    int mx_in_range = get_max_range(i, r-1, 1, 0, nt-1);
      |                      ~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~
horses.cpp:121:7: warning: unused variable 'val' [-Wunused-variable]
  121 |    ll val =  Y[mx_in_range];
      |       ^~~
horses.cpp:135:31: warning: 'mx_1' may be used uninitialized in this function [-Wmaybe-uninitialized]
  135 |   if (mult_range >= last_mult || mult_range * Y[i] >= last_mult)
      |       ~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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