Sort an Array
LeetCode https://leetcode.cn/problems/sort-an-array/
Quicksort
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class Solution {
public int[] sortArray(int[] nums) {
if (nums == null || nums.length <= 1) {
return nums;
}
// quick sorting
quickSortHelper(nums, 0, nums.length - 1);
return nums;
}
public void quickSortHelper(int[] a, int lo, int hi) {
if (hi <= lo)
return;
int pivot = partition(a, lo, hi);
quickSortHelper(a, lo, pivot - 1);
quickSortHelper(a, pivot + 1, hi);
}
public static int partition(int[] a, int lo, int hi) {
int i = lo;
int j = hi + 1;
int pivot = a[lo];
while (true) {
while (a[++i] < pivot)
if (i == hi)
break;
while (pivot < a[--j])
if (j == lo)
break;
if (i >= j)
break;
exch(a, i, j);
}
exch(a, lo, j);
return j;
}
public static void exch(int[] a, int i, int j) {
int swap = a[i];
a[i] = a[j];
a[j] = swap;
}
}
Complexity
- Time = O(nlog(n))
- Space = O(log(n))
Mergesort
Heapsort
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