Class Solution

leetcode/src/NextPermutationLeetCodeSolution.java:2–32

Problem: https://leetcode.com/explore/interview/card/google/59/array-and-strings/3050/

/** Problem: https://leetcode.com/explore/interview/card/google/59/array-and-strings/3050/ */
public class Solution {
  public void nextPermutation(int[] nums) {
    int i = nums.length - 2;
    while (i >= 0 && nums[i + 1] <= nums[i]) {
      i--;
    }
    if (i >= 0) {
      int j = nums.length - 1;
      while (nums[j] <= nums[i]) {
        j--;
      }
      swap(nums, i, j);
    }
    reverse(nums, i + 1);
  }

  private void reverse(int[] nums, int start) {
    int i = start, j = nums.length - 1;
    while (i < j) {
      swap(nums, i, j);
      i++;
      j--;
    }
  }

  private void swap(int[] nums, int i, int j) {
    int temp = nums[i];
    nums[i] = nums[j];
    nums[j] = temp;
  }
}