Submission #1191002

#	Time	Username	Problem	Language	Result	Execution time	Memory
1191002		Math4Life2020	Red-blue table (IZhO19_stones)	C++20	100 / 100	39 ms	2224 KiB

stones

#include <bits/stdc++.h>
using namespace std;
using ll = long long; using pii = pair<ll,ll>;

void solve() {
	//cout << "f1\n";
	ll N,M; cin >> N >> M;
	ll ans = 0; ll ac = 0; ll bc = 0;
	for (ll a=0; a<=N; a++) {
		for (ll b=0;b<=M;b++) { //N=1,M=3 -> a=0,b=3
			//need >=(M+1)/2 on a
			ll na = max(0LL,M/2+1-(M-b));
			ll nb = max(0LL,N/2+1-(N-a));
			if ((na*a+nb*b)<=(a*b)) {
				if (ans<(a+b)) {
					ans = a+b; ac = a; bc = b;
				}
			}
		}
	}
	cout << ans << "\n";
	bool isa[N][M];
	for (ll a1 = ac; a1<N; a1++) {
		for (ll b1 = 0; b1<M; b1++) {
			isa[a1][b1]=0;
		}
	}
	for (ll a1=0;a1<ac;a1++) {
		for (ll b1=0; b1<M; b1++) { //now switch the center chunk to be Bs if necessary
			isa[a1][b1]=1;
		}
	}
	set<ll> s0;
	for (ll b1=0;b1<bc;b1++) {
		ll nb = max(0LL,N/2+1-(N-ac));
		for (ll t=0;t<nb;t++) {
			if (s0.size()==0) {
				for (ll a1=0;a1<ac;a1++) {
					s0.insert(a1);
				}
			}
			assert(!s0.empty());
			ll x0 = *s0.begin(); s0.erase(s0.begin());
			isa[x0][b1]=0;
		}
	}
	for (ll a1=0;a1<N;a1++) {
		for (ll b1=0;b1<M;b1++) {
			cout << (isa[a1][b1] ? "+" : "-");
		}
		cout << "\n";
	}
}

int main() {
	ios_base::sync_with_stdio(false); cin.tie(0);
	ll T; cin >> T;
	while (T--) solve();
}

• Subtask 1: 17 / 17
• Subtask 2: 10 / 10
• Subtask 3: 16 / 16
• Subtask 4: 11 / 11
• Subtask 5: 15 / 15
• Subtask 6: 31 / 31