Submission #1004884

#	Time	Username	Problem	Language	Result	Execution time	Memory
1004884		magikarp23	Horses (IOI15_horses)	C++17	34 / 100	1593 ms	19948 KiB

horses

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

const int MAX_N = 500000 + 1;
const int MOD = 1000000007; // 10^9 + 7

int X_store[MAX_N];
int Y_store[MAX_N];
double log_X[MAX_N];
double log_cumsum[MAX_N];
int N_store;

void precompute_logs() {
    log_cumsum[0] = 0;
    for (int i = 0; i < N_store; i++) {
        log_X[i] = log(X_store[i]);
        log_cumsum[i + 1] = log_cumsum[i] + log_X[i];
    }
}

long long mod_pow(long long base, int exp) {
    long long result = 1;
    while (exp > 0) {
        if (exp & 1)
            result = (result * base) % MOD;
        base = (base * base) % MOD;
        exp >>= 1;
    }
    return result;
}

int calc_max_profit() {
    precompute_logs();
    
    int best_index = 0;
    double max_value = log_cumsum[1] + log(Y_store[0]);
    
    for (int i = 1; i < N_store; i++) {
        double current_value = log_cumsum[i + 1] + log(Y_store[i]);
        if (current_value > max_value) {
            max_value = current_value;
            best_index = i;
        }
    }
    
    long long profit = 1;
    for (int i = 0; i <= best_index; i++) {
        profit = (profit * X_store[i]) % MOD;
    }
    profit = (profit * Y_store[best_index]) % MOD;
    
    return static_cast<int>(profit);
}

int init(int N, int X[], int Y[]) {
    N_store = N;
    for (int i = 0; i < N; i++) {
        X_store[i] = X[i];
        Y_store[i] = Y[i];
    }
    return calc_max_profit();
}

int updateX(int pos, int val) {
    X_store[pos] = val;
    return calc_max_profit();
}

int updateY(int pos, int val) {
    Y_store[pos] = val;
    return calc_max_profit();
}

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