215. Kth Largest Element in an Array

最新推荐文章于 2022-07-02 13:48:51 发布

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本文介绍了一种在未排序数组中查找第K大元素的方法。通过将数组排序后直接返回第K大元素的方式实现，时间复杂度为O(nlogn)。

Find the kth largest element in an unsorted array. Note that it is the kth largest element in the sorted order, not the kth distinct element.
For example
Given [3,2,1,5,6,4] and k = 2, return 5.
Note:
You may assume k is always valid, 1 ≤ k ≤ array’s length.
Credits:
Special thanks to @mithmatt for adding this problem and creating all test cases.

class Solution {
public:
    int findKthLargest(vector<int>& nums, int k) {
        int * arr = new int[nums.size()];
        int index =0 ;
        for (vector<int>::iterator it = nums.begin();
         it != nums.end(); it++) {
            arr[index] = *it;
            index++;
        }
         sort(arr, arr + nums.size());
        index = nums.size();
        int temp = arr[nums.size() - k];
        delete arr;
        return temp;
    }

};