Submission #312643

#	Time	Username	Problem	Language	Result	Execution time	Memory
312643		joseacaz	Horses (IOI15_horses)	C++17	17 / 100	1578 ms	40676 KiB

horses

#include "horses.h"
#include <bits/stdc++.h>
#define pb push_back
#define all(x) x.begin(), x.end()

using namespace std;
using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using vi = vector<int>;
using vl = vector<ll>;
using vpi = vector<pii>;
using vpl = vector<pll>;

struct Node
{
    double pre, tot;
    int x;
};

const ll MOD = 1e9 + 7;
const int MAXN = 5e5 + 5;
int N;
ll X[MAXN], Y[MAXN];
double a[MAXN];
Node ST[4*MAXN];

Node operator +(const Node& _x, const Node& _y)
{
    Node tmp;
    tmp.pre = _x.pre;
    tmp.x = _x.x;
    tmp.tot = _x.tot + _y.tot;
    
    if(_x.tot + _y.pre > _x.pre)
    {
        tmp.pre = _x.tot + _y.pre;
        tmp.x = _y.x;
    }
    
    return tmp;
}

void build(int node = 0, int l = 0, int r = N - 1)
{
    if(l == r)
    {
        ST[node] = Node{a[l], a[l], l};
        //cerr << l << ", " << r << " : " << a[l] << " " << a[l] << " " << l << "\n";
        return;
    }
    
    int mid = (l+r)/2, lchild = 2*node + 1, rchild = 2*node + 2;
    build(lchild, l, mid);
    build(rchild, mid + 1, r);
    ST[node] = ST[lchild] + ST[rchild];
    //cerr << l << ", " << r << " : " << ST[node].pre << " " << ST[node].tot << " " << ST[node].x << "\n";
}

void upd(int pos, double x, int node = 0, int l = 0, int r = N - 1)
{
    if(r < pos || pos < l)
        return;
    if(l == r)
    {
        a[l] = x;
        ST[node] = Node{x, x, l};
        //cerr << l << ", " << r << " : " << ST[node].pre << " " << ST[node].tot << " " << ST[node].x << "\n";
        return;
    }

    int mid = (l+r)/2, lchild = 2*node + 1, rchild = 2*node + 2;
    upd(pos, x, lchild, l, mid);
    upd(pos, x, rchild, mid + 1, r);
    ST[node] = ST[lchild] + ST[rchild];
    //cerr << l << ", " << r << " : " << ST[node].pre << " " << ST[node].tot << " " << ST[node].x << "\n";
}

int init(int _N, int _X[], int _Y[])
{
    N = _N;
    for(int i = 0; i < N; i++)
    {
        X[i] = _X[i];
        Y[i] = _Y[i];
    }

    a[0] = log(X[0]) + log(Y[0]);
    for(int i = 1; i < N; i++)
        a[i] = log(X[i]) + log(Y[i]) - log(Y[i - 1]);
    build();
    
    int idx = ST[0].x;
    ll ans = 1;
    //cerr << "\n" << idx << "\n";
    for(int i = 0; i <= idx; i++)
    {
        ans *= X[i];
	    ans %= MOD;
    }
    ans *= Y[idx];
    ans %= MOD;
    return ans;
}

int updateX(int pos, int val)
{
    upd(pos, log(val) - log(X[pos]));
    X[pos] = val;

	int idx = ST[0].x;
    ll ans = 1;
    //cerr << ST[0].x << "\n";
    for(int i = 0; i <= idx; i++)
    {
        ans *= X[i];
	    ans %= MOD;
    }
    ans *= Y[idx];
    ans %= MOD;
    return ans;
}

int updateY(int pos, int val)
{
	upd(pos, log(val) - log(Y[pos]));
	upd(pos + 1, log(Y[pos]) - log(val));
    Y[pos] = val;

	int idx = ST[0].x;
    ll ans = 1;
    //cerr << ST[0].x << "\n";
    for(int i = 0; i <= idx; i++)
    {
        ans *= X[i];
	    ans %= MOD;
    }
    ans *= Y[idx];
    ans %= MOD;
    return ans;
}

Compilation message (stderr)

horses.cpp: In function 'int init(int, int*, int*)':
horses.cpp:103:12: warning: conversion from 'll' {aka 'long long int'} to 'int' may change value [-Wconversion]
  103 |     return ans;
      |            ^~~
horses.cpp: In function 'int updateX(int, int)':
horses.cpp:121:12: warning: conversion from 'll' {aka 'long long int'} to 'int' may change value [-Wconversion]
  121 |     return ans;
      |            ^~~
horses.cpp: In function 'int updateY(int, int)':
horses.cpp:140:12: warning: conversion from 'll' {aka 'long long int'} to 'int' may change value [-Wconversion]
  140 |     return ans;
      |            ^~~

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