Submission #316228

#	Time	Username	Problem	Language	Result	Execution time	Memory
316228		mohamedsobhi777	Horses (IOI15_horses)	C++14	34 / 100	1594 ms	18168 KiB

horses

#include "horses.h"
#include <bits/stdc++.h>
#pragma GCC optimize("trapv")

using namespace std;
using ll = long long;
using ld = long double;

const int _N = 5e5 + 7, mod = 1e9 + 7;
const ll inf = 2e18;
int n, m;
ll X[_N], Y[_N];
ll bit[_N];
double bit2[_N];

inline ll mul(ll x, ll y) { return 1ll * (x % mod) * (y % mod) % mod; }
ll faspow(ll x, ll y)
{
        if (!y)
                return 1ll;
        ll ret = faspow(x, y / 2);
        ret = 1ll * ret * ret % mod;
        if (y & 1)
                ret = 1ll * ret * x % mod;
        return ret;
}
inline ll inv(ll x) { return faspow(x, mod - 2); }
inline ll add(ll x, ll y) { return (x + y >= mod ? x + y - mod : x + y); }

void add(int x, ll v, ll old = 1ll)
{
        ++x;
        for (; x < _N; x += x & -x)
                bit[x] = mul(bit[x], mul(v, inv(old)));
}

ll eval(int x)
{
        ++x;
        ll ret = 1ll;
        for (; x; x -= x & -x)
                ret = 1ll * ret * bit[x] % mod;
        return ret;
}

void add2(int pos, double v)
{
        ++pos;
        for (; pos < _N; pos += pos & -pos)
                bit2[pos] += v;
}

double get2(int pos)
{
        ++pos;
        double ret = 0;
        for (; pos; pos -= pos & -pos)
                ret += bit2[pos];
        return ret;
}

ll solve()
{
        ll ret = 1ll;
        ll suf = 1ll;
        int i = n - 1;
        int cnt = 0;
        double tot = 0;
        double mx = 0;
        int k = 0;

        int de = n - 1;
        double lg = 0;
        for (int j = n - 1; ~j; --j)
        {
                lg += log(X[j]);
                de = j;
                if (lg > log(1e9))
                {
                        break;
                }
        }
        tot = get2(de - 1);
        for (int j = de; j < n; ++j)
        {
                tot += log(X[j]);
                if (tot + log(Y[j]) > mx)
                {
                        k = j;
                        mx = tot + log(Y[j]);
                }
        }
        return mul(eval(k), Y[k]);
}

int init(int N, int _X[], int _Y[])
{
        n = N;
        fill(bit, bit + _N, 1);
        for (int i = 0; i < N; ++i)
        {
                add(i, _X[i]);
                add2(i, _X[i]);
                X[i] = _X[i];
                Y[i] = _Y[i];
        }
        return solve();
}

int updateX(int pos, int val)
{
        add(pos, val, X[pos]);
        add2(pos, log(val) - log(X[pos]));
        X[pos] = val;
        return solve();
}

int updateY(int pos, int val)
{
        Y[pos] = val;
        return solve();
}

Compilation message (stderr)

horses.cpp: In function 'll solve()':
horses.cpp:64:12: warning: unused variable 'ret' [-Wunused-variable]
   64 |         ll ret = 1ll;
      |            ^~~
horses.cpp:65:12: warning: unused variable 'suf' [-Wunused-variable]
   65 |         ll suf = 1ll;
      |            ^~~
horses.cpp:66:13: warning: unused variable 'i' [-Wunused-variable]
   66 |         int i = n - 1;
      |             ^
horses.cpp:67:13: warning: unused variable 'cnt' [-Wunused-variable]
   67 |         int cnt = 0;
      |             ^~~
horses.cpp: In function 'int init(int, int*, int*)':
horses.cpp:107:21: warning: conversion from 'll' {aka 'long long int'} to 'int' may change value [-Wconversion]
  107 |         return solve();
      |                ~~~~~^~
horses.cpp: In function 'int updateX(int, int)':
horses.cpp:115:21: warning: conversion from 'll' {aka 'long long int'} to 'int' may change value [-Wconversion]
  115 |         return solve();
      |                ~~~~~^~
horses.cpp: In function 'int updateY(int, int)':
horses.cpp:121:21: warning: conversion from 'll' {aka 'long long int'} to 'int' may change value [-Wconversion]
  121 |         return solve();
      |                ~~~~~^~

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