Submission #761457

#	Time	Username	Problem	Language	Result	Execution time	Memory
761457		NK_	Red-blue table (IZhO19_stones)	C++17	100 / 100	46 ms	2524 KiB

stones

// Success consists of going from failure to failure without loss of enthusiasm
#include <bits/stdc++.h>

using namespace std;

#define nl '\n'

template<class T> using V = vector<T>;
using str = string;

void solve() {
	int N, M; cin >> N >> M;

	bool SWAP = 0;
	if (N < M) { swap(N, M); SWAP = 1; }

	// WLOG N > M

	int have = (M - 1) / 2;
	int need = (N / 2) + 1;

	// cout << N << " : " << M << endl;
	// cout << have << " - " << need << endl;
	int can = (have * N) / need;
	// cout << have * N << " - " << need << endl;

	int ans = min(M, can) + N; //??????

	V<str> A(N, str(M, '+'));

	set<pair<int, int>> S;
	for(int i = 0; i < N; i++) S.insert(make_pair(have, i));

	for(int c = 0; c < can; c++) {
		V<pair<int, int>> add;

		for(int t = 0; t < need; t++) {
			if (size(S) == 0) assert(false);
			
			int amt, i; tie(amt, i) = *rbegin(S);
			// cout << amt << " " << i << endl;
			S.erase(prev(end(S)));

			A[i][c] = '-'; amt--;
			if (amt > 0) add.push_back(make_pair(amt, i));
		}

		for(auto p : add) S.insert(p);
	}

	// for(auto x : A) cout << x << nl;

	if (SWAP) {
		V<str> B(M, str(N, '_'));
		for(int r = 0; r < N; r++) for(int c = 0; c < M; c++) {
			B[c][r] = '+' + '-' - A[r][c];
		}
		A.swap(B);
		swap(N, M);
	}

	cout << ans << nl;
	for(auto x : A) cout << x << nl;

	auto checker = [&]() {
		int ANS = 0;
		for(int r = 0; r < N; r++) {
			int x = 0;
			for(int c = 0; c < M; c++) x += (A[r][c] == '+');
			if (x > (M - x)) ANS++;
		}

		for(int c = 0; c < M; c++) {
			int x = 0;
			for(int r = 0; r < N; r++) x += (A[r][c] == '-');
			if (x > (N - x)) ANS++;
		}
		// cout << ANS << endl;

		if (ANS != ans) {
			cout << N << " <--> " << M << endl;
			assert(false);
		}
		assert(ANS == ans);
	};

	checker();

}

int main() {
	cin.tie(0)->sync_with_stdio(0);
	
	int T; cin >> T;
	while(T--) solve();

    return 0;
}

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