2160. Minimum Sum of Four Digit Number After Splitting Digits

/*
Get all digits of num.
Sort them.
To get the minimum sum. We need to choose 1st and 2nd digits as tens digits and 3rd and 4th as ones digits.
As when the tens digits will be minimum, then only we will get minimum sum.
For example:
5643=>3,4,5,6
30+40+5+6=86(min)

Other possibilities:
30+50+4+6=90
30+60+4+5=101
40+50+4+6=100 and so on.

Method 1:
Time complexity: O(nlogn)
Use array to store the digits of num.
*/

class Solution {
    public int minimumSum(int num) {
        int[] res=new int[4];
        int i=0;
        while(num>0){
            res[i]=num%10;
            num/=10;
            i++;
        }
        Arrays.sort(res)
        return res[0]*10+res[2]+res[1]*10+res[3];
    }
}





//method 2
/*
Method 2:
Use priorityqueue to store the digits of num.
Time complexity: O(n)
*/


class Solution {
    public int minimumSum(int num) {
        PriorityQueue<Integer>pq=new PriorityQueue<>();
		//complexity to insert: O(1)
        while(num>0){
            pq.offer(num%10);
            num/=10;
        }
		//complexity to remove: O(n)
        int a=10*pq.remove();
        int b=10*pq.remove();
        int c=pq.remove();
        int d=pq.remove();
        return a+b+c+d;
    }
}