Minimum Adjacent Swaps to Reach the Kth Smallest Number.java

// Runtime: 34 ms (Top 61.80%) | Memory: 42.9 MB (Top 13.48%)
class Solution {
    public int getMinSwaps(String num, int k) {
        int[] nums=new int[num.length()];
        int[] org=new int[num.length()];

        for(int i=0;i<num.length();i++){
            int e=Character.getNumericValue(num.charAt(i));
            nums[i]=e;
            org[i]=e;
        }

        while(k!=0){
        nextPermutation(nums);
         k--;
        }

        int ans=0;

        for(int i=0;i<nums.length;i++){

            if(nums[i]!=org[i]){
                int j=0;
                for(j=i+1;j<nums.length;j++)
                    if(org[j]==nums[i])
                        break;

                while(j>0 && j!=i){
                    swap(org,j,j-1);
                    ans++;
                    j--;
                }

            }

    }

      return ans;

    }

public void nextPermutation(int[] nums) {

        if(nums.length<=1)
            return;

        int j=nums.length-2;
       while(j>=0 && nums[j]>=nums[j+1])
           j--;

        if(j>=0){
        int k=nums.length-1;
        while(nums[j]>=nums[k])
            k--;

        swap(nums,j,k);

        }

        reverse(nums,j+1,nums.length-1);

    }

    public void swap(int[] nums,int j,int k){
        int temp=nums[j];
            nums[j]=nums[k];
            nums[k]=temp;
    }

    public void reverse(int[] nums,int i,int j){
        while(i<=j){
            swap(nums,i,j);
                i++;
                j--;
        }
    }
}