Submission #62286

#	Time	Username	Problem	Language	Result	Execution time	Memory
62286		Tenuun	Horses (IOI15_horses)	C++17	17 / 100	61 ms	28900 KiB

horses

//#include "horses.h"
#include<bits/stdc++.h>
#define mod 1000000007
#define ll long long
using namespace std;

int n, tr[1500000];
ll now=1;
vector<int>x, y, a;

void pre(){
	int last=-1;
	a.push_back(0);
	for(int i=1; i<n; i++){
		if(x[i]>1){
			a.push_back(i);
		}
	}
}

void build(int ind, int l, int r){
	if(l==r){
		tr[ind]=y[l];
		return;
	}
	build(ind*2, l, (l+r)/2);
	build(ind*2+1, (l+r)/2+1, r);
	tr[ind]=max(tr[ind*2], tr[ind*2+1]);
}

void upd(int ind, int l, int r, int L, int val){
	if(l==r) tr[ind]=val;
	int m=(l+r)/2;
	if(L<=m) upd(ind*2, l, m, L, val);
	else upd(ind*2+1, m+1, r, L, val);
}

ll rmq(int ind, int l, int r, int L, int R){
	if(l==L && r==R) return tr[ind];
	int m=(l+r)/2;
	if(R<=m) return rmq(ind*2, l, m, L, R);
	else if(L>m) return rmq(ind*2+1, m+1, r, L, R);
	else{
		return max(rmq(ind*2, l, m, L, m), rmq(ind*2+1, m+1, r, m+1, R));
	}
}

ll find(){
	int last=a.size()-1, ind=a.size();
	ll ans=1;
	ll now=rmq(1, 0, n-1, a[last], n-1);
	for(int i=a.size()-1; i>=0 && now<mod; i--){
		if(now*x[a[i]]>mod) break;
		now*=x[a[i]];
		ind=i;
	}
	ans=now;
	now/=rmq(1, 0, n-1, a[last], n-1);
	for(int i=a.size()-2; i>=ind; i--){
		now/=x[a[i+1]];
		ans=max(ans, now*rmq(1, 0, n-1, a[i], a[i+1]-1));
	}
	for(int i=ind-1; i>=0; i--){
		ans*=x[i];
		ans%=mod;
	}
	return ans;
}

int init(int N, int X[], int Y[]) {
	n=N;
	for(int i=0; i<n; i++) {x.push_back(X[i]); y.push_back(Y[i]);}
	pre();
	build(1, 0, n-1);
	return find();
}

int updateX(int pos, int val){

	return 0;
}

int updateY(int pos, int val){
	upd(1, 0, n-1, pos, val);
	return 0;
}

Compilation message (stderr)

horses.cpp: In function 'void pre()':
horses.cpp:12:6: warning: unused variable 'last' [-Wunused-variable]
  int last=-1;
      ^~~~
horses.cpp: In function 'long long int find()':
horses.cpp:49:19: warning: conversion to 'int' from 'std::vector<int>::size_type {aka long unsigned int}' may alter its value [-Wconversion]
  int last=a.size()-1, ind=a.size();
           ~~~~~~~~^~
horses.cpp:49:33: warning: conversion to 'int' from 'std::vector<int>::size_type {aka long unsigned int}' may alter its value [-Wconversion]
  int last=a.size()-1, ind=a.size();
                           ~~~~~~^~
horses.cpp:51:5: warning: declaration of 'now' shadows a global declaration [-Wshadow]
  ll now=rmq(1, 0, n-1, a[last], n-1);
     ^~~
horses.cpp:8:4: note: shadowed declaration is here
 ll now=1;
    ^~~
horses.cpp:52:20: warning: conversion to 'int' from 'std::vector<int>::size_type {aka long unsigned int}' may alter its value [-Wconversion]
  for(int i=a.size()-1; i>=0 && now<mod; i--){
            ~~~~~~~~^~
horses.cpp:59:20: warning: conversion to 'int' from 'std::vector<int>::size_type {aka long unsigned int}' may alter its value [-Wconversion]
  for(int i=a.size()-2; i>=ind; i--){
            ~~~~~~~~^~
horses.cpp: In function 'int init(int, int*, int*)':
horses.cpp:75:13: warning: conversion to 'int' from 'long long int' may alter its value [-Wconversion]
  return find();
         ~~~~^~
horses.cpp: In function 'int updateX(int, int)':
horses.cpp:78:17: warning: unused parameter 'pos' [-Wunused-parameter]
 int updateX(int pos, int val){
                 ^~~
horses.cpp:78:26: warning: unused parameter 'val' [-Wunused-parameter]
 int updateX(int pos, int val){
                          ^~~

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