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];
}
}
}