Submission #1033254

#	Time	Username	Problem	Language	Result	Execution time	Memory
1033254		socpite	Horses (IOI15_horses)	C++17	100 / 100	375 ms	53432 KiB

horses

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

const int maxn = 5e5+5;
const int mod = 1e9+7;

int st_max[4*maxn], st_prod[4*maxn];

int mult[maxn], cost[maxn];

int n;

void build(int X[], int Y[], int l = 0, int r = n-1, int id = 1){
	if(l == r){
		st_max[id] = Y[l];
		st_prod[id] = X[l];
	}
	else {
		int mid = (l+r)>>1;
		build(X, Y, l, mid, id<<1);
		build(X, Y, mid+1, r, id<<1|1);
		st_max[id] = max(st_max[id<<1], st_max[id<<1|1]);
		st_prod[id] = 1LL*st_prod[id<<1]*st_prod[id<<1|1]%mod;
	}
}

void edit_max(int pos, int val, int l = 0, int r = n-1, int id = 1){
	if(l == r)st_max[id] = val;
	else {
		int mid = (l+r)>>1;
		if(pos <= mid)edit_max(pos, val, l, mid, id<<1);
		else edit_max(pos, val, mid+1, r, id<<1|1);
		st_max[id] = max(st_max[id<<1], st_max[id<<1|1]);
	}
}

int get_max(int ql, int qr, int l = 0, int r = n-1, int id = 1){
	if(ql > r || l > qr)return 0;
	if(ql <= l && r <= qr)return st_max[id];
	int mid = (l+r)>>1;
	return max(get_max(ql, qr, l, mid, id<<1), get_max(ql, qr, mid+1, r, id<<1|1));
}

void edit_prod(int pos, int val, int l = 0, int r = n - 1, int id = 1){
	if(l == r)st_prod[id] = val;
	else {
		int mid = (l+r)>>1;
		if(pos <= mid)edit_prod(pos, val, l, mid, id<<1);
		else edit_prod(pos, val, mid+1, r, id<<1|1);
		st_prod[id] = 1LL*st_prod[id<<1]*st_prod[id<<1|1]%mod;
	}
}

int get_prod(int ql, int qr, int l = 0, int r = n-1, int id = 1){
	if(ql > r || l > qr)return 1;
	if(ql <= l && r <= qr)return st_prod[id];
	int mid = (l+r)>>1;
	return 1LL*get_prod(ql, qr, l, mid, id<<1)*get_prod(ql, qr, mid+1, r, id<<1|1)%mod;
}


set<int> st;

int solve(){
	int best = 0, bcost = 0, prv = n;
	long long mx = 0;
	for(auto it = st.rbegin(); it != st.rend(); it++){
		int nw = get_max(*it, prv - 1);
		// cout << nw << " " << mx << endl;
		if(nw > mx){
			mx = nw;
			best = *it;
			bcost = nw;
		}
		mx*=mult[*it];
		if(mx >= mod)break;
	}
	return 1LL*get_prod(0, best)*bcost%mod;
}

int init(int N, int X[], int Y[]) {
	n = N;
	build(X, Y);
	for(int i = 0; i < N; i++){
		mult[i] = X[i];
		cost[i] = Y[i];
		if(X[i] > 1)st.insert(i);
	}
	st.insert(0);
	return solve();
}

int updateX(int pos, int val) {	
	if(mult[pos] > 1)st.erase(pos);
	mult[pos] = val;
	edit_prod(pos, val);
	if(mult[pos] > 1)st.insert(pos);
	st.insert(0);
	return solve();
}

int updateY(int pos, int val) {
	cost[pos] = val;
	edit_max(pos, val);
	return solve();
}

Compilation message (stderr)

horses.cpp: In function 'void build(int*, int*, int, int, int)':
horses.cpp:24:52: warning: conversion from 'long long int' to 'int' may change value [-Wconversion]
   24 |   st_prod[id] = 1LL*st_prod[id<<1]*st_prod[id<<1|1]%mod;
      |                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~
horses.cpp: In function 'void edit_prod(int, int, int, int, int)':
horses.cpp:51:52: warning: conversion from 'long long int' to 'int' may change value [-Wconversion]
   51 |   st_prod[id] = 1LL*st_prod[id<<1]*st_prod[id<<1|1]%mod;
      |                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~
horses.cpp: In function 'int get_prod(int, int, int, int, int)':
horses.cpp:59:80: warning: conversion from 'long long int' to 'int' may change value [-Wconversion]
   59 |  return 1LL*get_prod(ql, qr, l, mid, id<<1)*get_prod(ql, qr, mid+1, r, id<<1|1)%mod;
      |         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~
horses.cpp: In function 'int solve()':
horses.cpp:79:36: warning: conversion from 'long long int' to 'int' may change value [-Wconversion]
   79 |  return 1LL*get_prod(0, best)*bcost%mod;
      |         ~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~

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