Submission #1279356

#	Time	Username	Problem	Language	Result	Execution time	Memory
1279356		swishy123	Horses (IOI15_horses)	C++20	17 / 100	1595 ms	16076 KiB

horses

#include <stdio.h>
#include <stdlib.h>
#include <bits/stdc++.h>

#define ll long long
using namespace std;

const int def = 5e5+1;
const ll mod = 1e9+7;

ll powmod(ll a, ll b){
    if (b == 0)
        return 1;
    if (b % 2 == 0){
        ll val = powmod(a, b / 2);
        return (val * val) % mod;
    }
    else
        return (a * powmod(a, b - 1)) % mod;
}
ll inv(ll x){
    return powmod(x, mod - 2);
}

ll bit[def];
void apply(int u, ll val){
    for (int i = u; i < def; i += i & -i)
        (bit[i] *= val) %= mod; 
}
ll query(int u){
    ll res = 1;
    for (int i = u; i > 0; i -= i & -i)
        (res *= bit[i]) %= mod;
    return res;
}

ll x[def], y[def];
int n;

int get(){
    int l = n - 1;
    __int128_t crr = x[l];

    __int128_t bound = (__int128_t)1e18 * (__int128_t)1e9;
    while (l - 1 >= 0 && (crr * x[l - 1]) <= bound)
        l--;
    
    ll prefix = query(l);
    __int128_t best = 1;

    crr = 1;
    for (int i = l; i < n; i++){
        crr *= x[i];
        __int128_t val = crr * y[i];

        best = max(best, val);
    }
    best %= mod;
    ll res = (prefix * best) % mod;
    return res;
}

int init(int N, int X[], int Y[]){
    for (int i = 0; i < def; i++)
        bit[i] = 1;
	n = N;
    for (int i = 0; i < n; i++){
        x[i] = X[i];
        apply(i + 1, x[i]);
        y[i] = Y[i];
    }
    return get();
}

int updateX(int pos, int val){	
    apply(pos + 1, ((ll)inv(x[pos]) * (ll)val) % mod);
    x[pos] = val;
	return get();
}

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

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