Submission #5102971

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Source Code Expand

#include "bits/stdc++.h"
using namespace std;
#ifdef _DEBUG
#include "dump.hpp"
#else
#define dump(...)
#endif

#define int long long
#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define rrep(i,a,b) for(int i=(b)-1;i>=(a);i--)
#define all(c) begin(c),end(c)
const int INF = sizeof(int) == sizeof(long long) ? 0x3f3f3f3f3f3f3f3fLL : 0x3f3f3f3f;
const int MOD = 1'000'000'007;
template<class T> bool chmax(T &a, const T &b) { if (a < b) { a = b; return true; } return false; }
template<class T> bool chmin(T &a, const T &b) { if (b < a) { a = b; return true; } return false; }



signed main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	int n, s; cin >> n >> s;

	int sq = ceil(sqrt(n));

	int ans = -1;

	rep(b, 2, sq + 1) {
		int m = n;
		int res = 0;
		while (m) {
			res += m % b;
			m /= b;
		}
		if (res == s) {
			ans = b;
			break;
		}
	}

	if (ans == -1) {
		for (int p = sq; p >= 1; p--) {
			int d = n / p;
			if (p >= d)continue;
			int r = n % d;
			int A = p + p * d + r - s;
			int B = p;
			int b = A / B;
			int q = (d - b) * p + r;
			if (A % B == 0 && q < b && q >= 0) {
				dump(p, d, q, p + q, b);
				ans = b;
				break;
			}
		}
	}

	cout << ans << endl;

	return 0;
}

Submission Info

Judge Result