Educational Codeforces Round 96 (Rated for Div. 2) （A - C题个人题解）

因为火锅导致错过的上分机会😂,赛后发现人均AC5题

1430A. Number of Apartments

暴力搜索

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
ll n;
void solve() {
	cin >> n;
	//bool flag = false;
	for (int i = 0; i * 3 <= n; i++) 
		for (int j = 0; j * 5 <= n; j++) 
			if ((n - i * 3 - j * 5) % 7 == 0) {
				cout << i << " " << j << " " << (n - i * 3 - j * 5) / 7 << endl;
				return;
			}
	cout << -1 << endl;
}

int main() {
	//freopen("in.txt", "r", stdin);
	ios_base::sync_with_stdio(false), cin.tie(0), cout.tie(0);
	int _; cin >> _; while (_--)solve();
}

1430B. Barrels

对水桶排序,累加后面k个水量即可

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 2e5 + 100;
ll n, k, a[N];
void solve() {
    cin >> n >> k;
    for (ll i = 0; i < n; i++)  cin >> a[i]; 
    sort(a, a + n);ll l = a[n - 1];
    for (ll i = n - 2; i >= n - k - 1; i--) { l += a[i]; }cout << l << endl;
}

int main() {
	int _; cin >> _; while (_--)solve();
}

1430C. Numbers on Whiteboard

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 2e5 + 100;
ll n, k, a[N], _, m;
void solve() {
    cin >> n; m = n; k = n - 1;
    cout << 2 << '\n';
    for (int i = 2; i <= n; ++i) {
        cout << k << ' ' << m << '\n';
        m = (k + m + 1) / 2; --k;
    }
}
int main() {
    int _; cin >> _; while (_--)solve();
}