题解 | #最大乘积#

import java.util.*;

public class Main { public static void main(String[] args) { Scanner in = new Scanner(System.in); int n = in.nextInt(); if (n < 3) return;

    in.nextLine();
    String[] str = in.nextLine().split(" ");
    long[] arr = new long[n];
    for (int i = 0; i < n; i++) {
        arr[i] = Long.valueOf(str[i]);
    }
    System.out.println(getMaxProduct(arr, n));
}

public static long getMaxProduct(long[] arr, int n) {
    if (n == 3) {
        return arr[0] * arr[1] * arr[2];
    }
    long max1 = Integer.MIN_VALUE, max2 = Integer.MIN_VALUE,
         max3 = Integer.MIN_VALUE, min1 = Integer.MAX_VALUE, min2 = Integer.MAX_VALUE;
    long res = Integer.MIN_VALUE;
    for (int i = 0; i < n; i++) {
        if (arr[i] > max1) {
            max3 = max2;
            max2 = max1;
            max1 = arr[i];
        } else if (arr[i] > max2) {
            max3 = max2;
            max2 = arr[i];
        } else if (arr[i] > max3) {
            max3 = arr[i];
        }
        if (arr[i] < min1) {
            min2 = min1;
            min1 = arr[i];
        } else if (arr[i] < min2) {
            min2 = arr[i];
        }
    }
    res = Math.max(max1 * max2 * max3, min1 * min2 * max1);
    return res ;
}

}