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Next Permutation

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Linkage

https://leetcode.com/problems/next-permutation/description/

Code

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class Solution {
    
    public void nextPermutation(int[] nums) {
        if (nums.length == 0 || nums.length == 1){
            return;
        }
        
        int current = nums[nums.length-1];
        int index = nums.length - 2;
        while(index >= 0 && nums[index] >= current){
            current = nums[index];
            index -= 1;
        }
        
        
        //Reverse Array directly
        if (index < 0){
            reverseArray(nums);
            return;
        }
        
        //Find the min element but larger than current itme in subarray
        int min = 100000;
        int min_index = -1;
        for(int i = index+1; i <= nums.length-1; i++) {
            if ( nums[i] > nums[index] && nums[i] < min ) {
                min = nums[i];
                min_index = i;
            }
        }
        
        
        //Swap
        int temp = nums[index];
        nums[index] = nums[min_index];
        nums[min_index] = temp;
        
        //Sor in ascending order
        Arrays.sort(nums, index+1, nums.length);
    }
    
    public void reverseArray(int[] nums){
        int[] temp = new int[nums.length];
        for (int i = 0; i < nums.length; i++) {
            temp[i] = nums[nums.length-i-1];
        }
        for (int i = 0; i < nums.length; i++) {
            nums[i] = temp[i];
        }
        
    }
}