Submission #69038

#	Time	Username	Problem	Language	Result	Execution time	Memory
69038		theknife2001	Horses (IOI15_horses)	C++17	37 / 100	262 ms	29828 KiB

horses

#include "horses.h"
#include <bits/stdc++.h>
#define mid (l+r)/2



using namespace std;
const int N=5e5+55;
long long tree[N*4][2];
long long x[N];
long long y[N];
int m=1e9+7;
int cnt=0;

int n;


void build(int l , int r , int node)
{
    if(l==r)
    {
        tree[node][0]=x[l];
        tree[node][1]=y[l];
        return ;
    }
    build(l,mid,node*2);
    build(mid+1,r,node*2+1);
    tree[node][0]=tree[node*2][0]*tree[node*2+1][0];
    tree[node][0]%=m;
    tree[node][1]=tree[node*2][1]*tree[node*2+1][1];
    tree[node][1]%=m;
}

void update(int l , int r , int node , int ind , int val , int q)
{
    if(l==r&&l==ind)
    {
        tree[node][q]=val;
        return ;
    }
    if(ind<=mid)
        update(l,mid,node*2,ind,val,q);
    else
        update(mid+1,r,node*2+1,ind,val,q);
    tree[node][q]=tree[node*2][q]*tree[node*2+1][q];
    tree[node][q]%=m;
}

long long query(int l , int r , int node , int x , int y , int q)
{
    if(x<=l&&r<=y)
        return tree[node][q];
    if(l>y||r<x)
        return 1;
    return (query(l,mid,node*2,x,y,q)*query(mid+1,r,node*2+1,x,y,q))%m;

}

int solve()
{
	int i=n-1;
    long long ret=0;
	long long temp=1;
	long long s=1;
	while(i>=0)
    {
        s*=x[i];
        i--;
        if(s>10000000000)
        {
            i++;
            break;
        }
    }
    i++;
    int bestpos=n-1;
    for(;i<n;i++)
    {
        temp*=x[i];
        if(y[i]*temp>ret)
        {
            ret=y[i]*temp;
            bestpos=i;
        }
        if(ret<0||y[i]*temp<0)
        {
            assert(0);
        }
    }
    return (y[bestpos]*query(0,n-1,1,0,bestpos,0))%m;
}

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];
    }
    build(0,n-1,1);
    return solve();
}

int updateX(int pos, int val) {
    x[pos]=val;
    update(0,n-1,1,pos,val,0);
    return solve();
}

int updateY(int pos, int val)
{
    y[pos]=val;
    update(0,n-1,1,pos,val,1);
    return solve();
}

Compilation message (stderr)

horses.cpp: In function 'long long int query(int, int, int, int, int, int)':
horses.cpp:49:65: warning: declaration of 'y' shadows a global declaration [-Wshadow]
 long long query(int l , int r , int node , int x , int y , int q)
                                                                 ^
horses.cpp:11:11: note: shadowed declaration is here
 long long y[N];
           ^
horses.cpp:49:65: warning: declaration of 'x' shadows a global declaration [-Wshadow]
 long long query(int l , int r , int node , int x , int y , int q)
                                                                 ^
horses.cpp:10:11: note: shadowed declaration is here
 long long x[N];
           ^
horses.cpp: In function 'int solve()':
horses.cpp:90:51: warning: conversion to 'int' from 'long long int' may alter its value [-Wconversion]
     return (y[bestpos]*query(0,n-1,1,0,bestpos,0))%m;
            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~
horses.cpp: In function 'int init(int, int*, int*)':
horses.cpp:93:33: warning: declaration of 'N' shadows a global declaration [-Wshadow]
 int init(int N, int X[], int Y[])
                                 ^
horses.cpp:8:11: note: shadowed declaration is here
 const int N=5e5+55;
           ^

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