Submission #1085334

#	Time	Username	Problem	Language	Result	Execution time	Memory
1085334		guagua0407	Horses (IOI15_horses)	C++17	100 / 100	609 ms	80472 KiB

horses

#include "horses.h"
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pii pair<int,int>
#define f first
#define s second
#define all(x) x.begin(),x.end()
#define _ ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);

int n;
vector<ll> x,y;
const ll inf=1e9;
const ll mod=1e9+7;
vector<ll> segtree,segtreemx;
set<int> S;

void update(int pos,int val,int l=0,int r=n-1,int v=1){
    if(l==r){
        segtree[v]=val;
        return;
    }
    int mid=(l+r)/2;
    if(pos<=mid) update(pos,val,l,mid,v*2);
    else update(pos,val,mid+1,r,v*2+1);
    segtree[v]=segtree[v*2]*segtree[v*2+1]%mod;
}

ll query(int tl,int tr,int l=0,int r=n-1,int v=1){
    if(r<tl or tr<l){
        return 1;
    }
    if(tl<=l and r<=tr){
        return segtree[v];
    }
    int mid=(l+r)/2;
    return query(tl,min(mid,tr),l,mid,v*2)*query(max(mid+1,tl),tr,mid+1,r,v*2+1)%mod;
}

void updatemx(int pos,int val,int l=0,int r=n-1,int v=1){
    if(l==r){
        segtreemx[v]=val;
        return;
    }
    int mid=(l+r)/2;
    if(pos<=mid) updatemx(pos,val,l,mid,v*2);
    else updatemx(pos,val,mid+1,r,v*2+1);
    segtreemx[v]=max(segtreemx[v*2],segtreemx[v*2+1]);
}

ll querymx(int tl,int tr,int l=0,int r=n-1,int v=1){
    if(r<tl or tr<l){
        return 0;
    }
    if(tl<=l and r<=tr){
        return segtreemx[v];
    }
    int mid=(l+r)/2;
    return max(querymx(tl,min(mid,tr),l,mid,v*2),querymx(max(mid+1,tl),tr,mid+1,r,v*2+1));
}

ll go(){
    ll cur=0;
    int prv=n;
    ll ans=1;
    int best=-1;
    for(auto it=S.rbegin();it!=S.rend();it++){
        int pos=*it;
        ll mx=querymx(max(pos,0),prv-1);
        //return mx;
        if(mx>cur){
            cur=mx;
            ans=query(0,pos)*mx%mod;
            best=pos;
            //if(pos==0) return query(0,pos);
        }
        if(pos!=-1){
            if(cur*x[pos]>inf) break;
            cur*=x[pos];
        }
        prv=pos;
    }
	return ans;
}

int init(int N, int X[], int Y[]) {
    n=N;
    x.resize(n);
    y.resize(n);
    segtree=vector<ll>(4*n,1);
    segtreemx=vector<ll>(4*n,1);
    S.insert(-1);
    for(int i=0;i<n;i++){
        x[i]=X[i];
        y[i]=Y[i];
        update(i,x[i]);
        updatemx(i,y[i]);
        if(x[i]>1) S.insert(i);
    }
    return go();
}

int updateX(int pos, int val) {
    if(x[pos]>1) S.erase(pos);
    x[pos]=val;
    if(x[pos]>1) S.insert(pos);
    update(pos,x[pos]);
    return go();
}

int updateY(int pos, int val) {
    y[pos]=val;
    updatemx(pos,y[pos]);
    return go();
}

Compilation message (stderr)

horses.cpp: In function 'long long int go()':
horses.cpp:66:9: warning: variable 'best' set but not used [-Wunused-but-set-variable]
   66 |     int best=-1;
      |         ^~~~
horses.cpp: In function 'int init(int, int*, int*)':
horses.cpp:96:22: warning: conversion from '__gnu_cxx::__alloc_traits<std::allocator<long long int>, long long int>::value_type' {aka 'long long int'} to 'int' may change value [-Wconversion]
   96 |         update(i,x[i]);
      |                      ^
horses.cpp:97:24: warning: conversion from '__gnu_cxx::__alloc_traits<std::allocator<long long int>, long long int>::value_type' {aka 'long long int'} to 'int' may change value [-Wconversion]
   97 |         updatemx(i,y[i]);
      |                        ^
horses.cpp:100:14: warning: conversion from 'long long int' to 'int' may change value [-Wconversion]
  100 |     return go();
      |            ~~^~
horses.cpp: In function 'int updateX(int, int)':
horses.cpp:107:22: warning: conversion from '__gnu_cxx::__alloc_traits<std::allocator<long long int>, long long int>::value_type' {aka 'long long int'} to 'int' may change value [-Wconversion]
  107 |     update(pos,x[pos]);
      |                      ^
horses.cpp:108:14: warning: conversion from 'long long int' to 'int' may change value [-Wconversion]
  108 |     return go();
      |            ~~^~
horses.cpp: In function 'int updateY(int, int)':
horses.cpp:113:24: warning: conversion from '__gnu_cxx::__alloc_traits<std::allocator<long long int>, long long int>::value_type' {aka 'long long int'} to 'int' may change value [-Wconversion]
  113 |     updatemx(pos,y[pos]);
      |                        ^
horses.cpp:114:14: warning: conversion from 'long long int' to 'int' may change value [-Wconversion]
  114 |     return go();
      |            ~~^~

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