Submission #1208163

#	Time	Username	Problem	Language	Result	Execution time	Memory
1208163		NK_	Sprinklers (CEOI24_sprinklers)	C++20	9 / 100	45 ms	6340 KiB

Main

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

using namespace std;

#define nl '\n'
#define sz(x) int(x.size())
#define pb push_back
#define eb emplace_back

using str = string;
template<class T> using V = vector<T>;
// template<class T> using pq = priority_queue<T, vector<T>, greater<T>>;
using vs = V<str>;
using vi = V<int>;

int main() {
	cin.tie(0)->sync_with_stdio(0);
	
	int N, M; cin >> N >> M;
	vi A(N); for(auto& x : A) cin >> x;
	vi B(M); for(auto& x : B) cin >> x;

	set<int> has(begin(A), end(A));
	{
		vi C; for(auto& x : B) if (!has.count(x)) C.pb(x);
		B = C;
	}

	// if (A[0] > B.front() && A[0] < B.back()) {
	// 	cout << -1 << nl;
	// 	exit(0-0);
	// }	

	// if (A[0] > B.front()) cout << A[0] - B.front() << nl << "L" << nl;
	// else cout << B.back() - A[0] << nl << "R" << nl;
	// exit(0-0);

	auto chk = [&](int k) {

		str ans(N, 'L');

		int i = 0, j = 0;
		while(i < M) {
			// find the min j s.t. you match this flower with this sprinkler

			if (j == N) break;
			while(j < N && abs(B[i] - A[j]) > k) j++;
			if (j == N) break;

			int bnd = -1;
			if (A[j] < B[i]) bnd = A[j] + k, ans[j] = 'R';
			else bnd = A[j], ans[j] = 'L';

			// cout << j << " " << ans[j] << endl;
			// cout << i << endl;

			j++;
			while(i < M && B[i] <= bnd) i++;
		}

		if (i != M) return str("-1");
		return ans;
	};

	int lo = 0, hi = 1e9 + 10;
	while(lo < hi) {
		int mid = (lo + hi) / 2;
		// cout << mid << endl;
		if (chk(mid) != "-1") hi = mid;
		else lo = mid + 1;
	}


	str ans = chk(lo);
	if (ans != "-1") {
		cout << lo << nl;
		// assert(lo == max(abs(A.front() - B.front()), abs(A.front() - B.back())));
	}
	cout << ans << nl;

	exit(0-0);
}

// Breathe In, Breathe Out

• Subtask 0: 0 / 0
• Subtask 1: 3 / 3
• Subtask 2: 6 / 6
• Subtask 3: 0 / 17
• Subtask 4: 0 / 27
• Subtask 5: 0 / 47