Merge pull request wangzheng0822#275 from luanheart/master

fix bug java.12_sorts.KthSmallest

Author: wangzheng0822

java/12_sorts/KthSmallest.java

@@ -27,8 +27,9 @@ private static int partition(int[] arr, int p, int r) {
  int pivot = arr[r];
 
  int i = p;
- for (int j = p; j <= r - 1; j++) {
- if (arr[j] < pivot) {
+ for (int j = p; j < r; j++) {
+ // 这里要是 <= ，不然会出现死循环，比如查找数组 [1,1,2] 的第二小的元素
+ if (arr[j] <= pivot) {
  swap(arr, i, j);
  i++;
  }