POTD/GFG_Second Smallest number.cpp at main · SHIVAAYgod/POTD · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
class Solution{
  public:
string secondSmallest(int S, int D){
         if(S==1 || D==1) return "-1";
         if(S>9*D) return "-1";
         if(S==9*D) return "-1";

         string ans(D,'0');
         int sum=S;
         int last=-1;

         // First Smallest Number
         for(int i=D-1;i>=0;i--)
         {
             if(sum>9)
             {
                 ans[i]='9';
                 sum-=9;
             }
             else if(sum>0)
             {
                 ans[i]='0'+sum;
                 last=i;
                 sum=0;
             }
             else
             {
                 ans[i]='0';
             }
         }

         if(ans[0]=='0')
         {
             ans[0]='1';
             ans[last]-=1;
         }

         // Second Smallest Number
         int l=D-2;
         while(ans[l]=='9') l--;

         ans[l]+=1;
         ans[l+1]-=1;

         return ans;
    }
};