Submission #719407

#	Time	Username	Problem	Language	Result	Execution time	Memory
719407		thimote75	Horses (IOI15_horses)	C++14	17 / 100	1554 ms	22032 KiB

horses

#include "horses.h"

#include <bits/stdc++.h>
using namespace std;

#define ld long double

const ld MOD = 1e9 + 7;

ld exp_table[25];

void init_exp_table () {
	exp_table[0] = exp(1.0);

	for (int j = 1; j < 25; j ++) {
		exp_table[j] = exp_table[j - 1] * exp_table[j - 1];
		exp_table[j] = fmod(exp_table[j], MOD);
	}
}

ld mod_exp (int n) {
	ld res = 1;

	for (int k = 0; k < 25; k ++) {
		if (((1 << k) & n) != 0) {
			res *= exp_table[k];
			res  = fmod(res, MOD);
		}
	}

	return res;
}
int mod_exp (ld doub) {
	int n = (int) floor(doub);
	ld f0 = mod_exp(n);

	ld om = doub - n;

	return round(fmod(f0 * exp(om), MOD));
}

vector<ld> lX;
vector<ld> lY;

int compute () {
	ld max_v = 0;
	ld sum_v = 0;

	for (int j = 0; j < lX.size(); j ++) {
		sum_v += lX[j];

		max_v = max(max_v, sum_v + lY[j]);
	}

	return mod_exp(max_v);
}

int init(int N, int X[], int Y[]) {
	init_exp_table();
	lX.resize(N);
	lY.resize(N);

	for (int i = 0; i < N; i ++) {
		lX[i] = log((ld) X[i]);
		lY[i] = log((ld) Y[i]);
	}

	return compute();
}

int updateX(int pos, int val) {
	lX[pos] = log((ld) val);
	return compute();
}

int updateY(int pos, int val) {
	lY[pos] = log((ld) val);
	return compute();
}

Compilation message (stderr)

horses.cpp: In function 'int mod_exp(long double)':
horses.cpp:39:14: warning: conversion from 'long double' to 'int' may change value [-Wfloat-conversion]
   39 |  return round(fmod(f0 * exp(om), MOD));
      |         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
horses.cpp: In function 'int compute()':
horses.cpp:49:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long double>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   49 |  for (int j = 0; j < lX.size(); j ++) {
      |                  ~~^~~~~~~~~~~

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