3637383940414243444546474849505152535455565758596061626364656667686970717273747576

import java.util.*;

// Solution class
class Solution {
    // Function to find next permutation
    public void nextPermutation(int[] nums) {
        // Set index to -1
        int index = -1;

        // Find the first decreasing element from end
        for (int i = nums.length - 2; i >= 0; i--) {
            // If smaller found
            if (nums[i] < nums[i + 1]) {
                // Store index
                index = i;
                break;
            }
        }

        // If no index found
        if (index == -1) {
            // Reverse the entire array
            reverse(nums, 0, nums.length - 1);
            return;
        }

        // Find just larger element
        for (int i = nums.length - 1; i > index; i--) {
            // Swap them
            if (nums[i] > nums[index]) {
                swap(nums, i, index);
                break;
            }
        }

        // Reverse part after index
        reverse(nums, index + 1, nums.length - 1);
    }

    // Helper to reverse array
    private void reverse(int[] arr, int start, int end) {
        while (start < end) {
            swap(arr, start, end);
            start++;
            end--;
        }
    }

    // Helper to swap
    private void swap(int[] arr, int i, int j) {
        int temp = arr[i];
        arr[i] = arr[j];
        arr[j] = temp;
    }
}

// Main class
public class Main {
    public static void main(String[] args) {
        // Input array
        int[] nums = {1, 2, 3};

        // Create object
        Solution sol = new Solution();

        // Call function
        sol.nextPermutation(nums);

        // Print result
        for (int num : nums) {
            System.out.print(num + " ");
        }
        System.out.println();
    }
}

1234567891011121314151617181920212223242526272829303132333435363738394041424344454647

# Solution class
class Solution:
    # Function to find next permutation
    def nextPermutation(self, nums):
        # Set index
        index = -1

        # Find decreasing point
        for i in range(len(nums) - 2, -1, -1):
            # If smaller found
            if nums[i] < nums[i + 1]:
                index = i
                break

        # If no such index
        if index == -1:
            # Reverse whole list
            nums.reverse()
            return

        # Find just greater element
        for i in range(len(nums) - 1, index, -1):
            if nums[i] > nums[index]:
                # Swap them
                nums[i], nums[index] = nums[index], nums[i]
                break

        # Reverse part after inde