Submission #337362

#TimeUsernameProblemLanguageResultExecution timeMemory
337362blueHorses (IOI15_horses)C++11
17 / 100
1609 ms130412 KiB
#include "horses.h"
#include <algorithm>
#include <iostream>
#include <vector>
#include <string>
#include <set>
using namespace std;
 
 
long long mod = 1e9 + 7;
 
class segtree
{
public:
    int l;
    int r;
    long long mx;
    long long p;
 
    segtree* left = NULL;
    segtree* right = NULL;
 
    segtree()
    {
        ;
    }
 
    segtree(int L, int R)
    {
        l = L;
        r = R;
        mx = p = 1;
        if(l == r) return;
        int m = (l+r)/2;
        left = new segtree(l, m);
        right = new segtree(m+1, r);
    }
 
    long long rangemax(int L, int R)
    {
        if(R < l || r < L) return 0;
        if(L <= l && r <= R) return mx;
        return max(left->rangemax(L, R), right->rangemax(L, R));
    }
 
    long long rangeprod(int L, int R)
    {
        if(R < l || r < L) return 1;
        if(L <= l && r <= R) return p;
        return (left->rangeprod(L, R) * right->rangeprod(L, R)) % mod;
    }
 
    void update(int I, long long V)
    {
        if(I < l || r < I) return;
        if(l == r) mx = p = V;
        else
        {
            left->update(I, V);
            right->update(I, V);
            mx = max(left->mx, right->mx);
            p = (left->p * right->p) % mod;
        }
    }
};
 
struct growth
{
    int i;
    long long x;
};
 
bool operator < (growth A, growth B)
{
    return A.i > B.i;
}
 
int N;
segtree X;
segtree Y;
set<growth> Xset;
 
int compute()
{
    long long fullprod = 1;
    int fullprod_pos = N;
    for(growth g: Xset)
    {
        if(fullprod * g.x > 1e9)
        {
            fullprod_pos = g.i + 1;
            break;
        }
        fullprod *= g.x;
        fullprod_pos = g.i;
    } //fullprod_pos is the leftmost position such that Xproduct(fullprod_pos, N-1) < 1e9
      //The leftmost selling point is fullprod_pos - 1
 
    long long res = 1;
    int res_pos = 0;
 
    for(growth g: Xset)
    {
        if(g.i < fullprod_pos - 1) break;
        if(X.rangeprod(fullprod_pos, g.i) * Y.rangemax(g.i, N-1) > res)
        {
            res = X.rangeprod(fullprod_pos, g.i) * Y.rangemax(g.i, N-1);
            res_pos = g.i;
        }
    }
    return int( (X.rangeprod(0, res_pos) * Y.rangemax(res_pos, N-1)) % mod );
}
 
int init(int n, int x[], int y[])
{
    N = n;
    X = segtree(0, N);
    Y = segtree(0, N);
 
    for(int i = 0; i < N; i++)
    {
        X.update(i, x[i]);
        Y.update(i, y[i]);
 
        if(x[i] != 1) Xset.insert(growth{i, x[i]});
    }
    X.update(N, 1);
    Y.update(N, 0);
    Xset.insert(growth{N, 1});
 
    return compute();
}
 
int updateX(int pos, int val)
{
    X.update(pos, val);
    Xset.erase(growth{pos, val});
    if(val != 1) Xset.insert(growth{pos, val});
 
    // cout << "after update: \n";
    // for(int i = 0; i < N; i++) cout << X.rangemax(i, i) << ' ';
    // cout << '\n';
    // for(int i = 0; i < N; i++) cout << Y.rangemax(i, i) << ' ';
    // cout << '\n';
 
    return compute();
}
 
int updateY(int pos, int val)
{
    Y.update(pos, val);
 
    // cout << "after update: \n";
    // for(int i = 0; i < N; i++) cout << X.rangemax(i, i) << ' ';
    // cout << '\n';
    // for(int i = 0; i < N; i++) cout << Y.rangemax(i, i) << ' ';
    // cout << '\n';
 
    return compute();
}

Compilation message (stderr)

horses.cpp: In function 'int compute()':
horses.cpp:89:21: warning: conversion from 'long long int' to 'double' may change value [-Wconversion]
   89 |         if(fullprod * g.x > 1e9)
      |            ~~~~~~~~~^~~~~
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