Submission #733922

#	Time	Username	Problem	Language	Result	Execution time	Memory
733922		vjudge1	City Mapping (NOI18_citymapping)	C++17	25 / 100	33 ms	852 KiB

citymapping

#include "citymapping.h"
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
constexpr ll inf = 1e15;
void find_roads(int N, int Q, int A[], int B[], int W[]) {
    int r = -1;
    ll mx = 0;
    for (int i = 1; i < N; i++) {
		assert(Q--);
		ll s = get_distance(1, i + 1);
		if (s > mx) {
			mx = s;
			r = i;
		}
	}
	vector<ll> dis(N);
	for (int i = 0; i < N; i++) {
		assert(Q--);
		dis[i] = i == r ? 0 : get_distance(r + 1, i + 1);
	}
	vector<int> p(N);
	iota(p.begin(), p.end(), 0);
	sort(p.begin(), p.end(), [&](int i, int j) {
		return dis[i] < dis[j];
	});
	vector<vector<int>> ch(N);
	for (int i = 1; i < N; i++) {
		int x = r, v = p[i];
		while (1) {
			if (ch[x].empty()) {
				A[i - 1] = x + 1;
				B[i - 1] = v + 1;
				W[i - 1] = dis[v] - dis[x];
				ch[x].push_back(v);
				break;
			}
			if (x == r) {
				x = ch[x][0];
				continue;
			}
			if (ch[x].size() == 2) {
				assert(Q--);
				assert(Q--);
				if (dis[v] - dis[ch[x][0]] == get_distance(v + 1, ch[x][0] + 1)) {
					x = ch[x][0];
				} else {
					x = ch[x][1];
				}
			} else {
				assert(Q--);
				if (dis[v] - dis[ch[x][0]] != get_distance(v + 1, ch[x][0] + 1)) {
					A[i - 1] = x + 1;
					B[i - 1] = v + 1;
					W[i - 1] = dis[v] - dis[x];
					ch[x].push_back(v);
					break;
				}
				x = ch[x][0];
			}
		}
	}
}

• Subtask 1: 9 / 9
• Subtask 2: 16 / 16
• Subtask 3: 0 / 13
• Subtask 4: 0 / 19
• Subtask 5: 0 / 43