Submission #620743

#	Time	Username	Problem	Language	Result	Execution time	Memory
620743		Hazem	Horses (IOI15_horses)	C++14	37 / 100	100 ms	20644 KiB

horses

#include <bits/stdc++.h>
#define LL long long

using namespace std;

const int M = 5e5+10;
const int MOD = 1e9+7;

LL add(LL a,LL b){
	return (a+b)%MOD;
}

LL mult(LL a,LL b){
	return (a*b)%MOD;
}

LL fastpow(LL n,LL k){

	LL ret = 1;

	while(k){

		if(k&1)ret = mult(ret,n);
		k /= 2;
		n = mult(n,n);
	}
	return ret;
}

LL divide(LL a,LL b){
	return mult(a,fastpow(b,MOD-2));
}

LL a[M],b[M],n;
LL pr = 1;

LL calc(){

	LL idx = max(1ll,n-30),cur = 1;
	for(int i=idx+1;i<=n;i++){
		
		if((cur*a[i]>b[idx])||(cur*a[i]*b[i]>b[idx]))
			idx = i,cur = 1;
		else 
			cur *= a[i];
	}

	cur = 1;
	for(int i=max(1ll,n-30);i<=idx;i++)
		cur = mult(cur,a[i]);
	
	return mult(mult(cur,pr),b[idx]);
}

int init(int N, int X[], int Y[]) {
	
	n = N;
	a[0] = 1;
	for(int i=1;i<=n;i++){
		a[i] = X[i-1];
		b[i] = Y[i-1];
		if(i<n-30)
			pr = mult(pr,a[i]);
	}

	return calc();
}

int updateX(int pos, int val) {	
	
	if(pos+1<n-30){
		pr = divide(pr,a[pos+1]);
		pr = mult(pr,val);
	}
	a[pos+1] = val;

	return calc();
}

int updateY(int pos, int val) {
	
	b[pos+1] = val;

	return calc();
}

Compilation message (stderr)

horses.cpp: In function 'long long int calc()':
horses.cpp:40:15: warning: conversion from 'long long int' to 'int' may change value [-Wconversion]
   40 |  for(int i=idx+1;i<=n;i++){
      |            ~~~^~
horses.cpp:49:15: warning: conversion from 'long long int' to 'int' may change value [-Wconversion]
   49 |  for(int i=max(1ll,n-30);i<=idx;i++)
      |            ~~~^~~~~~~~~~
horses.cpp: In function 'int init(int, int*, int*)':
horses.cpp:66:13: warning: conversion from 'long long int' to 'int' may change value [-Wconversion]
   66 |  return calc();
      |         ~~~~^~
horses.cpp: In function 'int updateX(int, int)':
horses.cpp:77:13: warning: conversion from 'long long int' to 'int' may change value [-Wconversion]
   77 |  return calc();
      |         ~~~~^~
horses.cpp: In function 'int updateY(int, int)':
horses.cpp:84:13: warning: conversion from 'long long int' to 'int' may change value [-Wconversion]
   84 |  return calc();
      |         ~~~~^~

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