Submission #36066

#	Time	Username	Problem	Language	Result	Execution time	Memory
36066		UncleGrandpa925	Bootfall (IZhO17_bootfall)	C++14	65 / 100	1000 ms	4824 KiB

bootfall

/*input
4
1 3 1 5
*/
#include <bits/stdc++.h>
using namespace std;
#define sp ' '
#define endl '\n'
#define fi first
#define se second
#define mp make_pair
#define N 505
#define bit(x,y) ((x>>y)&1LL)
#define na(x) (#x) << ":" << x
ostream& operator << (ostream &os, vector<int>&x) {
	for (int i = 0; i < x.size(); i++) os << x[i] << sp;
	return os;
}
ostream& operator << (ostream &os, pair<int, int> x) {
	cout << x.fi << sp << x.se << sp;
	return os;
}
ostream& operator << (ostream &os, vector<pair<int, int> >&x) {
	for (int i = 0; i < x.size(); i++) os << x[i] << endl;
	return os;
}
const int mod = 1e9 + 7;

int n;
int a[N];
int f[250005];
int sum = 0;
int mark[250005];
vector<int> order;
bool used[N];

void add(int x) {
	for (int i = sum; i >= 0; i--) {
		f[i + x] += f[i];
		if (f[i + x] >= mod) f[i + x] -= mod;
	}
	sum += x;
}

void sub(int x) {
	for (int i = 0; i <= sum; i++) {
		f[i + x] += (mod - f[i]);
		if (f[i + x] >= mod) f[i + x] -= mod;
	}
	sum -= x;
}

signed main() {
	scanf("%d", &n);
	f[0] = 1;
	for (int i = 1; i <= n; i++) scanf("%d", &a[i]), add(a[i]);
	if (sum % 2 || f[sum / 2] == 0) {
		printf("0\n");
		return 0;
	}
	int cnt = 0;
	for (int i = 1; i <= n; i++) {
		if (used[a[i]]) continue;
		used[a[i]] = true; cnt++;
		sub(a[i]);
		int sta = 1; if (sum % 2 == 0) sta++;
		for (int j = sta; j <= sum; j += 2) {
			if (f[(sum + j) / 2 - j])
				mark[j]++;
		}
		add(a[i]);
	}
	for (int i = 1; i <= sum; i++) if (mark[i] == cnt) order.push_back(i);
	printf("%d\n", order.size());
	for (int i = 0; i < order.size(); i++) {
		printf("%d ", order[i]);
	}
}

Compilation message (stderr)

bootfall.cpp: In function 'std::ostream& operator<<(std::ostream&, std::vector<int>&)':
bootfall.cpp:16:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < x.size(); i++) os << x[i] << sp;
                    ^
bootfall.cpp: In function 'std::ostream& operator<<(std::ostream&, std::vector<std::pair<int, int> >&)':
bootfall.cpp:24:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < x.size(); i++) os << x[i] << endl;
                    ^
bootfall.cpp: In function 'int main()':
bootfall.cpp:74:29: warning: format '%d' expects argument of type 'int', but argument 2 has type 'std::vector<int>::size_type {aka long unsigned int}' [-Wformat=]
  printf("%d\n", order.size());
                             ^
bootfall.cpp:75:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < order.size(); i++) {
                    ^
bootfall.cpp:54:17: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &n);
                 ^
bootfall.cpp:56:60: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  for (int i = 1; i <= n; i++) scanf("%d", &a[i]), add(a[i]);
                                                            ^

• Subtask 1: 6 / 6
• Subtask 2: 7 / 7
• Subtask 3: 15 / 15
• Subtask 4: 16 / 16
• Subtask 5: 21 / 21
• Subtask 6: 0 / 35