Submission #577107

#	Time	Username	Problem	Language	Result	Execution time	Memory
577107		goodluck2020	Brunhilda’s Birthday (BOI13_brunhilda)	C++14	100 / 100	244 ms	80264 KiB

brunhilda

#define INPFILE "GROUP.INP"
#define OUTFILE "GROUP.OUT"

#include <bits/stdc++.h>
using namespace std;
bool maximise(int &a, int b) { return a < b ? a = b, true : false; }

const int MAX = 1e7 + 1, INF = 0x3f3f3f3f;

int n, Q, rmax[MAX], f[MAX];
bool used[MAX];
void input(void) {
	cin >> n >> Q;

	memset(rmax, 0, sizeof rmax);
	for (int i = 1; i <= n; i++) {
		int x; cin >> x;
		if (used[x]) continue;

		for (int j = x - 1; j < MAX; j += x)
			maximise(rmax[j], x - 1);

		maximise(rmax[MAX - 1], (MAX - 1) % x);
	}

	for (int i = MAX - 2; i >= 0; i--)
		maximise(rmax[i], rmax[i + 1] - 1);
}

int main(void) {
	if (fopen(INPFILE, "r")) {
		freopen(INPFILE, "r", stdin);
		freopen(OUTFILE, "w", stdout);
	}

	ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

	input();

	memset(f, 0x3f, sizeof f); f[0] = 0;
	for (int i = 1; i < MAX; i++)
		f[i] = f[i - rmax[i]] + 1;

	while (Q--) {
		int x; cin >> x;
		int ans = f[x];

		if (ans >= INF) cout << "oo\n";
		else cout << ans << '\n';
	}

	return 0;
}

Compilation message (stderr)

brunhilda.cpp: In function 'int main()':
brunhilda.cpp:32:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   32 |   freopen(INPFILE, "r", stdin);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
brunhilda.cpp:33:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   33 |   freopen(OUTFILE, "w", stdout);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 20 / 20
• Subtask 2: 20 / 20
• Subtask 3: 60 / 60