输入4个数字时如何求和3个最高数字

Question

I'm still learning how to use java, and I was wondering if there was a way to add the 3 highest numbers when a user inputs 4 numbers?

For Ex. the user enters 5 6 7 6, they would add 6 7 6 which would be 19.

The only idea I got was using and if else statement? But I feel like that wouldn't be efficient in my code.

Thanks in advanced

Answer 1

Assuming an int array and there'll only ever be 4 numbers entered, the problem can actually be rephrased as getting a sum with the minimum element of the array removed. Not that it matters much at this size, sorting incurs an O(nlogn) cost. Instead, just do it linearly in one loop by finding the min and removing it at the end.

int[] nums = { 5, 6, 7, 6 };
int min = Integer.MAX_VALUE;
int sum = 0;

for (int num : nums) {
    if (num < min) {
        min = num;
    }
    sum += num;
}

sum -= min;

System.out.println(sum);

Answer 2

use Array.sort

    int arr[] = {5,6,7,6};
    Arrays.sort(arr);
    int total = 0;
    for (int i = 3; i > 0; i--) // what a fool, it was the wrong way around
        total += arr[i];

    System.out.println(total);

Or you could use

    Integer arr[] = {5,10, 10, 10};
    Arrays.sort(arr, Collections.reverseOrder());

and loop normally from 0 to 3

Answer 3

I'd suggest you to first create a set and then sort. If you sort and sum, a test case such as

9, 5, 9, 7, 6, 2 will fail as the largest numbers in the array are 9,5,7 and after sorting you will only get 9,9,9 at the first three indices

by creating a set (no repetition)

The array would be 9,5,7,6,2 you can then sort it and sum the first three.

Answer 4

store them in array. sort the array. sum up the last 3 elements i,e

int[] arr={7,8,5,2,1,4,5};
Arrays.sort(arr);
int sum = 0;
        for(int i=arr.length-1;i>=arr.length-3;i--) {
            sum += arr[i];
        }
        System.out.println(sum);