Submission #1086294

#	Time	Username	Problem	Language	Result	Execution time	Memory
1086294		RiverFlow	Horses (IOI15_horses)	C++14	34 / 100	1593 ms	12180 KiB

horses

#include "horses.h"

#include <bits/stdc++.h>

using namespace std;

#define FOR(i, a, b) for(int i = (a); i <= (b); ++i)
#define FOD(i, b, a) for(int i = (b); i >= (a); --i)


const int N = (int)5e5 + 7;

const int mod = (int)1e9 + 7;

int add(int a, int b) { return a + b < mod ? a + b : a + b - mod; }
int sub(int a, int b) { return a >= b ? a - b : a - b + mod; }
int mul(int a, int b) { return 1LL * a * b % mod; }

int n, x[N], y[N];

#define nl "\n"
#define ll long long

const ll LIM = (int)1e10;

bool isSub2 = 1;

int fx() {
    ll mx = 0;
    int ans = 0;
    if (isSub2) {
        int p = 0;
        if (n > 36) p = n - 36;
        FOD(i, n - 1, p) {
            if (y[i] >= mx) {
                ans = i;
            }
            mx = max(mx, (ll)y[i]);
            mx = min(LIM, mx * x[i]);
        }
        return ans;
    }
    FOD(i, n - 1, 0) {
        if (y[i] >= mx) {
            ans = i;
        }
        mx = max(mx, (ll)y[i]);
        mx = min(LIM, mx * x[i]);
    }
    return ans;
}

int init(int N, int X[], int Y[]) {
    n = N;

    FOR(i, 0, n - 1) x[i] = X[i], y[i] = Y[i];

    isSub2 &= *min_element(x, x + n) >= 2;

    int px = fx(), ans = 1;
    FOR(i, 0, px) ans = mul(ans, x[i]);

    return mul(ans, y[px]);
}

// khi thay doi X -> nhan p(i >= pos) *= X'/X
// khi thay doi Y ->

int updateX(int pos, int val) {
    isSub2 &= val >= 2;
    x[pos] = val;
    int px = fx(), ans = 1;
    FOR(i, 0, px) ans = mul(ans, x[i]);

    return mul(ans, y[px]);
}

int updateY(int pos, int val) {
    y[pos] = val;
    int px = fx(), ans = 1;
    FOR(i, 0, px) ans = mul(ans, x[i]);

    return mul(ans, y[px]);
}

Compilation message (stderr)

horses.cpp: In function 'int mul(int, int)':
horses.cpp:17:44: warning: conversion from 'long long int' to 'int' may change value [-Wconversion]
   17 | int mul(int a, int b) { return 1LL * a * b % mod; }
      |                                ~~~~~~~~~~~~^~~~~
horses.cpp: In function 'int init(int, int*, int*)':
horses.cpp:53:14: warning: declaration of 'N' shadows a global declaration [-Wshadow]
   53 | int init(int N, int X[], int Y[]) {
      |          ~~~~^
horses.cpp:11:11: note: shadowed declaration is here
   11 | const int N = (int)5e5 + 7;
      |           ^

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