LeetCode215-kth-largest-element-in-an-array

第k 大的元素

这题用递归出错了，划不来，一点都不好debug, 最重要的是抽线能力

class Solution {
    public int findKthLargest(int[] nums, int k) {
        
        mergeSort(nums, 0, nums.length-1);
        int count = nums.length;
        return nums[count-k];
        
    }
      static public void mergeSort(int[] num, int left, int right){
        if(left<right) {
            int mid = (left + right) / 2;
            mergeSort(num,left,mid);
            mergeSort(num, mid + 1, right);
            mergeSort(num, left, mid, right);
        }

    }

    static public void mergeSort(int[] num, int left, int mid, int right){
        int[] sort = new int[num.length];

        int counter = left;
        int i = left;
        int j = mid+1;
        while(i <= mid && j <= right){

            if(num[i]>=num[j]){
                sort[counter] = num[j];
                j++;
            }else{
                sort[counter] = num[i];
                i++;
            }
            counter++;
        }
        while(i <= mid){
            sort[counter++] = num[i++];
        }
        while(j <= right){
            sort[counter++] = num[j++];
        }

        for(int k=left;k<=right;k++){
            num[k] = sort[k];
        }

    }

}