Commit 02b1769

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Improvement

Signed-off-by: begeekmyfriend <begeekmyfriend@gmail.com>

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Lines changed: 6 additions & 1 deletion

Original file line number	Diff line number	Diff line change
`@@ -62,6 +62,10 @@ static void quick_select(int *nums, int lo, int hi, int k)`
`62`	`62`	`* shall make the partition in the middle of the array as far as`
`63`	`63`	`* possible. If the partition is located in the head or tail, the`
`64`	`64`	`* performance might well be very bad for it.`
	`65`	`+ *`
	`66`	`+ * Note: Do NOT use nums[++i] <= pivot or nums[--j] >= pivot as the`
	`67`	`+ * loop condition because it leads to redundant operations in each`
	`68`	`+ * recusive iteration when there are many duplicate elements.`
`65`	`69`	`*/`
`66`	`70`	`while (i < hi && nums[++i] > pivot) {}`
`67`	`71`	`while (j > lo && nums[--j] < pivot) {}`
`@@ -72,7 +76,8 @@ static void quick_select(int *nums, int lo, int hi, int k)`
`72`	`76`
`73`	`77`	`/* invariant: i == j + 1 or i == j */`
`74`	`78`	`swap(&nums[i], &nums[hi]);`
`75`		`- if (i + 1 >= k) {`
	`79`	`+ /* compare index [i] with [k - 1] to locate the kth element */`
	`80`	`+ if (i > k - 1) {`
`76`	`81`	`quick_select(nums, lo, i - 1, k);`
`77`	`82`	`} else {`
`78`	`83`	`quick_select(nums, i + 1, hi, k);`

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