Submission #856731

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
const int MAX_N = 100030;    // Change as necessary

void check1(ll b,ll n,ll s){
  while(n){
    s -= n % b;
    n /= b;
  }
  
  if(s) return;
  
  cout << b << endl;
  exit(0);
}

bool check2(ll a1,ll n,ll s){
  n -= s;
  if(n <= 0) return 0;
  
  return (n % a1 == 0);
}

int main(){
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  
  ll n,s; cin >> n >> s;
  for(ll b=2;b<=1000000;b++)
    check1(b,n,s);
  
  vector<ll> poss;
  for(ll a1=1;a1<=1000000;a1++)
    if(check2(a1,n,s)){
      ll b = (n-s)/a1+1;
      ll a2 = s - a1;
      if(!(0 <= a2 && a2 < b)) continue;
      if(!(0 <= a1 && a1 < b)) continue;
      if(b > 1000000)
        poss.push_back(b);
    }
  
  if(n == s) poss.push_back(n+1);
  
  if(poss.empty())
    cout << -1 << endl;
  else
    cout << *min_element(poss.begin(),poss.end()) << endl;
  
  return 0;
}

Submission Info

Judge Result