分而治之——找出第K大的数

问题描述：

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.

Example 1:

Input: [3,2,1,5,6,4] and k = 2
Output: 5

Example 2:

Input: [3,2,3,1,2,4,5,5,6] and k = 4
Output: 4

问题解决：

利用堆排序：

class Solution {
public:
    int findKthLargest(vector<int>& nums, int k) {
        make_heap(nums.begin(), nums.end());
        for(int i = 0; i < k - 1; i++)
            pop_heap(nums.begin(), nums.end()-i);
        return *nums.begin();

    }
};