寻找一数组中前K个最大的数

考察点：数组

public int findKthLargest(int[] nums, int k) {    if (k < 1 || nums == null) {        return 0;    }      return getKth(nums.length - k +1, nums, 0,nums.length - 1);}  public int getKth(int k, int[] nums, int start, int end) {      int pivot = nums[end];      int left = start;    int right = end;      while (true) {          while (nums[left] < pivot && left < right) { left++;        }          while (nums[right] >= pivot && right > left) { right--;        }          if(left == right) { break;        }          swap(nums,left, right);    }      swap(nums, left, end);      if (k == left + 1) {        return pivot;    } else if (k < left + 1) {        return getKth(k, nums, start, left - 1);    } else {        return getKth(k, nums, left + 1, end);    }}  public void swap(int[] nums, int n1, int n2) {    int tmp = nums[n1];    nums[n1] = nums[n2];    nums[n2] = tmp;}