Submission #796694

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
796694	2023-07-28T15:46:18 Z	jasmin	Horses (IOI15_horses)	C++17	Compilation error	0 ms	0 KB

horses

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

int n=0;
vector<int> x;
vector<int> y;

const long long MOD=1e9+7;

int MUL(long long a, long long b){
    return (a*b)%MOD;
}

struct maxsegtree{
    vector<int> tree;

    void init(){
        tree.assign(n*4, 0);
    }

    int update(int l, int r, int v, int x, int val){
        if(x<l || r<=x) return tree[v];
        if(l+1==r){
            return tree[v]=val;
        }
        int m=l+(r-l)/2;
        return tree[v]=max(update(l, m, v*2+1, x, val), update(m, r, v*2+2, x, val));
    }

    int query(int l, int r, int v, int ql, int qr){
        if(qr<=l || r<=ql) return 1;
        if(ql<=l && r<=qr){
            return tree[v];
        }
        int m=l+(r-l)/2;
        return max(query(l, m, v*2+1, ql, qr), query(m, r, v*2+2, ql, qr));
    }
};
maxsegtree maxseg;

struct productsegtree{
    vector<int> tree;

    void init(){
        tree.assign(n*4, 1);
    }

    int update(int l, int r, int v, int x, int val){
        if(x<l || r<=x) return tree[v];
        if(l+1==r){
            return tree[v]=val;
        }
        int m=l+(r-l)/2;
        return tree[v] = MUL(update(l, m, v*2+1, x, val), update(m, r, v*2+2, x, val));
    }

    int query(int l, int r, int v, int ql, int qr){
        if(qr<=l || r<=ql) return 1;
        if(ql<=l && r<=qr){
            return tree[v];
        }
        int m=l+(r-l)/2;
        return MUL(query(l, m, v*2+1, ql, qr), query(m, r, v*2+2, ql, qr));
    }
};
productsegtree pseg;

set<int> notone;

bool bigger(pair<long long, long long> a, pair<long long, long long> b){
    return a.first*b.second > a.second*b.first;
}

int solve(){

    auto it=notone.end();
    long long product=1;

    pair<int, long long> best={1, 1};
    int ind=n-1;
    bool mod=false;
    while(!mod && it!=notone.begin()){
        it=prev(it);
        int pos=*it;

        int yfac=maxseg.query(0, n, 0, pos, n);

        if(bigger({yfac, product}, best)){
            best={yfac, product};
            ind=pos;
        }

        product*=x[pos];
        if(product>MOD){

            product%=MOD;
            mod=true;
        }
    }

    //check first one
    int yfac=maxseg.query(0, n, 0, 0, n);
    product=pseg.query(0, n, 0, 1, n);
    if(!mod && bigger({yfac, product}, best)){
        
        best={yfac, product};
        ind = 0;
    }
    

    int yfac=maxseg.query(0, n, 0, ind, n);
    int xfac=pseg.query(0, n, 0, 0, ind+1);

    int ans=MUL(xfac, yfac);
    return ans;
}

int init(int N, int X[], int Y[]) {
    
    n=N;
    x.assign(n, 0);
    for(int i=0; i<n; i++){
        x[i]=X[i];
    }
    y.assign(n, 0);
    for(int i=0; i<n; i++){
        y[i]=Y[i];
    }


    maxseg.init();
    for(int i=0; i<n; i++){
        maxseg.update(0, n, 0, i, y[i]);
    }
    pseg.init();
    for(int i=0; i<n; i++){
        pseg.update(0, n, 0, i, x[i]);
    }

    for(int i=0; i<n; i++){
        if(x[i]!=1){
            notone.insert(i);
        }
    }

    return solve();
}


int updateX(int pos, int val) {	

    if(x[pos]==1 && val!=1){
        notone.insert(pos);
    }
    if(x[pos]!=1 && val==1){
        notone.erase(pos);
    }

    x[pos]=val;
    pseg.update(0, n, 0, pos, val);
    
    return solve();
}

int updateY(int pos, int val) {
	
    y[pos]=val;
    maxseg.update(0, n, 0, pos, val);

    return solve();
}

Compilation message

horses.cpp: In function 'int MUL(long long int, long long int)':
horses.cpp:12:17: warning: conversion from 'long long int' to 'int' may change value [-Wconversion]
   12 |     return (a*b)%MOD;
      |            ~~~~~^~~~
horses.cpp: In member function 'int maxsegtree::update(int, int, int, int, int)':
horses.cpp:22:41: warning: declaration of 'x' shadows a global declaration [-Wshadow]
   22 |     int update(int l, int r, int v, int x, int val){
      |                                     ~~~~^
horses.cpp:6:13: note: shadowed declaration is here
    6 | vector<int> x;
      |             ^
horses.cpp: In member function 'int productsegtree::update(int, int, int, int, int)':
horses.cpp:49:41: warning: declaration of 'x' shadows a global declaration [-Wshadow]
   49 |     int update(int l, int r, int v, int x, int val){
      |                                     ~~~~^
horses.cpp:6:13: note: shadowed declaration is here
    6 | vector<int> x;
      |             ^
horses.cpp: In function 'int solve()':
horses.cpp:112:9: error: redeclaration of 'int yfac'
  112 |     int yfac=maxseg.query(0, n, 0, ind, n);
      |         ^~~~
horses.cpp:103:9: note: 'int yfac' previously declared here
  103 |     int yfac=maxseg.query(0, n, 0, 0, n);
      |         ^~~~