Smallest number 15-07-24 POTD.cpp

// https://www.geeksforgeeks.org/problems/smallest-number5829/1

class Solution {
  public:
    string smallestNumber(int s, int d) {
        if(s>9*d) return "-1";
        string res(d,' ');
        s--;
        for(int i=d-1;i>=1;i--){
            int diff=min(9,s); 
            res[i]='0'+diff;
            s-=diff;
        }
        
        res[0]='1'+s;
        return res;
    }
};