g0001_0100.s0031_next_permutation.Solution.cpp Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of leetcode-in-all Show documentation

104 LeetCode algorithm problem solutions

There is a newer version: 1.8

// #Medium #Top_100_Liked_Questions #Array #Two_Pointers #Big_O_Time_O(n)_Space_O(1)
// #2024_05_24_Time_0_ms_(100.00%)_Space_14.5_MB_(86.94%)

#include 
#include 
using namespace std;

class Solution {
public:
    void nextPermutation(vector& nums) {
        if (nums.size() <= 1) {
            return;
        }
        int i = nums.size() - 2;
        while (i >= 0 && nums[i] >= nums[i + 1]) {
            i--;
        }
        if (i >= 0) {
            int j = nums.size() - 1;
            while (nums[j] <= nums[i]) {
                j--;
            }
            swap(nums, i, j);
        }
        reverse(nums, i + 1, nums.size() - 1);
    }

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

    void reverse(vector& nums, int i, int j) {
        while (i < j) {
            swap(nums, i++, j--);
        }
    }
};