Submission #3470550

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Source Code Expand

#include <bits/stdc++.h>

#define For(i, l, r) for(register int i = (l), i##end = (int)(r); i <= i##end; ++i)
#define Fordown(i, r, l) for(register int i = (r), i##end = (int)(l); i >= i##end; --i)
#define Set(a, v) memset(a, v, sizeof(a))
#define Cpy(a, b) memcpy(a, b, sizeof(a))
#define debug(x) cout << #x << ": " << (x) << endl
#define DEBUG(...) fprintf(stderr, __VA_ARGS__)

using namespace std;

typedef long long ll;

template<typename T> inline bool chkmin(T &a, T b) { return b < a ? a = b, 1 : 0; }
template<typename T> inline bool chkmax(T &a, T b) { return b > a ? a = b, 1 : 0; }

void File() {
#ifdef zjp_shadow
	freopen ("B.in", "r", stdin);
	freopen ("B.out", "w", stdout);
#endif
}

ll n, S;

inline bool Check(int val) {
	ll tmp = n, res = 0;
	for (; tmp; tmp /= val)
		res += tmp % val;
	return res == S;
}

int main () {

	File();

	cin >> n >> S;

	int gap = sqrt(n + .5);
	For (i, 2, gap)
		if (Check(i)) return printf("%d\n", i), 0;
	
	for (ll i = gap + 1, Nexti; i <= n; i = Nexti + 1) {
		Nexti = n / (n / i);
		ll res = (S - n);
		if (res % (n / i)) continue ;
		res = res / (n / i);
		ll b = - res + 1;
		if (i <= b && b <= Nexti)
			return printf ("%lld\n", b), 0;
	}

	if (n == S)
		return printf("%lld\n", n + 1), 0;

	puts("-1");

	return 0;

}

Submission Info

Judge Result