提出 #27697585

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ソースコード 拡げる

#include <ctime>
#include <random>
#include <vector>
#include <iostream>
using namespace std;

vector<int> find_grouping(int N) {
	// Find one way to divide {1, 2, ..., N-1} into 3 groups
	random_device rd;
	uniform_int_distribution<int> p(1, 3);
	vector<int> g(N);
	while (clock() < 2.9 * CLOCKS_PER_SEC) {
		for (int i = 1; i < N; ++i) {
			g[i] = p(rd);
		}
		int sum1 = 0, sum2 = 0, sum3 = 0;
		for (int i = 1; i < N; ++i) {
			if (g[i] == 1) sum1 += i;
			if (g[i] == 2) sum2 += i;
			if (g[i] == 3) sum3 += i;
		}
		if (sum1 == sum2 && sum1 == sum3) {
			return g;
		}
	}
	return vector<int>(); // if not found, return empty vector
}

int main() {
	int N;
	cin >> N;
	vector<int> g = find_grouping(N);
	if (g == vector<int>()) {
		cout << "No" << endl;
	}
	else {
		cout << "Yes" << endl;
		for (int i = 0; i < N - 1; ++i) {
			for (int j = i + 1; j < N; ++j) {
				char color = '?';
				if (g[j] == 1) color = 'R';
				if (g[j] == 2) color = 'B';
				if (g[j] == 3) color = 'W';
				cout << color;
			}
			cout << endl;
		}
	}
	return 0;
}

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