LeetCode-215 - Kth largest element in an array

Kth largest element in an array

Topic description: Given an array of integers nums and an array of integers k , please return the **k** largest element in the array.

Note that you need to find the k th largest element of the sorted array, not the k th distinct element.

For example descriptions, please refer to the official website of LeetCode.

Source: LeetCode
Link: https://leetcode-cn.com/problems/kth-largest-element-in-an-array/
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Solution 1: Array sorting

The first consideration here is to sort the original array, and the kth largest element can be directly obtained from the sorted array, so the specific processing process is as follows:

• First, use the sorting algorithm to sort the array. There are various sorting algorithms, such as bubble sort, quick sort, merge sort, etc. Here, the java library function is directly used to sort the array, which is a lazy approach;
• Then according to the sorted array index, the Kth largest element can be directly obtained and returned.

 import java.util.Arrays;

public class LeetCode_215 {
    /**
     * 数组排序：首先使用排序算法对该数组排序，然后直接获取第K大的元素返回即可
     *
     * @param nums 原数组
     * @param k 期望的第K大
     * @return
     */
    public static int findKthLargest(int[] nums, int k) {
        // 排序算法有各种，这里直接使用了java的库函数进行排序
        Arrays.sort(nums);
        // 排序后，直接返回第K大的元素
        return nums[nums.length - k];
    }

    public static void main(String[] args) {
        int[] nums = new int[]{3, 2, 1, 5, 6, 4};
        // 测试用例，期望输出： 5
        System.out.println(findKthLargest(nums, 2));
    }
}

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