Submission #856987

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Source Code Expand

#include <algorithm>
#include <cfloat>
#include <climits>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <functional>
#include <iostream>
#include <map>
#include <memory>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <utility>
#include <vector>
#include <list>

using namespace std;

typedef long long ll;

#define sz size()
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define all(c) (c).begin(), (c).end()
#define rep(i,a,b) for(ll i=(a);i<(b);++i)
#define clr(a, b) memset((a), (b) ,sizeof(a))
#define ctos(d) string(1,d)
#define print(x) cout<<#x<<" = "<<x<<endl;

#define MOD 1000000007

ll d[1005][1005];

#define MAX_V 1005
#define INF 1000000000

ll n;
ll s;

ll f2(ll a) {
  ll n1 = n;
  ll c = 0;
  while (1) {
    c += n1 % a;
    n1 /= a;
    if (n1 == 0)break;
  }
  return c;
}

ll f(ll a) {
  ll n1 = n;
  ll c = 0;
  while (1) {
    c += n1 % a;
    n1 /= a;
    if (n1 == 0)break;
  }
  if (c >= s)return 1;
  return 0;
}

int main() {
  cin >> n >> s;
  long long low = 2;
  long long high = 100000000011LL;

  while (low < high) {
    long long mid = (high + low) >> 1;

    if (f(mid) == 1) {
      high = mid;
    }
    else {
      low = mid + 1;
    }
  }
  ll mn = 100000000011LL;
  rep(i,max(2LL,low-100000),min(100000000000LL,low+100000)){
    if(f2(i)==s){
      mn = min(mn,i);
    }
  }
  if(mn ==  100000000011LL){
    cout << -1 << endl;
  }
  else{
    cout << mn << endl;
  }
  return 0;
}

Submission Info

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