Day-6 Plus One

class Solution {
    public int[] plusOne(int[] digits) {
        int sum=0;
        int carry=1;
        
        for(int i=digits.length-1;i>=0;i--){
            sum=digits[i]+carry;
            carry=sum/10;
            digits[i]=sum%10;
        }
        
        if(carry>0){
            int[] newAr=new int[digits.length+1];
            for(int i=0;i<digits.length;i++){
                newAr[i+1]=digits[i];
            }
            newAr[0]=carry;
            return newAr;
        }
        return digits;
    }
}


class Solution {
  public int[] plusOne(int[] digits) {
    int n = digits.length;

    // move along the input array starting from the end
    for (int idx = n - 1; idx >= 0; --idx) {
      // set all the nines at the end of array to zeros
      if (digits[idx] == 9) {
        digits[idx] = 0;
      }
      // here we have the rightmost not-nine
      else {
        // increase this rightmost not-nine by 1 
        digits[idx]++;
        // and the job is done
        return digits;
      }
    }
    // we're here because all the digits are nines
    digits = new int[n + 1];
    digits[0] = 1;
    return digits;
  }
}