Submission #733966

#	Time	Username	Problem	Language	Result	Execution time	Memory
733966		vjudge1	City Mapping (NOI18_citymapping)	C++17	57 / 100	120 ms	8880 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[]) {
	if (Q == 500000) {
		vector<tuple<ll, int, int>> T;
		for (int i = 0; i < N; i++) {
			for (int j = i + 1; j < N; j++) {
				T.emplace_back(get_distance(i + 1, j + 1), i, j);
			}
		}
		sort(T.begin(), T.end());
		vector<int> par(N);
		iota(par.begin(), par.end(), 0);
		function<int(int)> find = [&](int x) {
			return x == par[x] ? x : par[x] = find(par[x]);
		};
		int p = 0;
		for (int i = 0; i < T.size(); i++) {
			auto [z, x, y] = T[i];
			if (find(x) != find(y)) {
				A[p] = x + 1;
				B[p] = y + 1;
				W[p] = z;
				p++;
				par[find(x)] = find(y);
			}
		}
		return;
	}
	if (Q == 12000) {
		int x = -1;
		ll mx = 0;
		for (int i = 1; i < N; i++) {
			ll s = get_distance(1, i + 1);
			if (s > mx) {
				mx = s;
				x = i;
			}
		}
		vector<pair<ll, int>> p(N);
		for (int i = 0; i < N; i++) {
			p[i] = {get_distance(x + 1, i + 1), i};
		}
		sort(p.begin(), p.end());
		for (int i = 0; i < N - 1; i++) {
			A[i] = p[i].second + 1;
			B[i] = p[i + 1].second + 1;
			W[i] = p[i + 1].first - p[i].first;
		}
		return;
	}
    int r = -1;
    ll mx = 0;
    for (int i = 1; i < N; i++) {
		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++) {
		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>> d(N);
	d[0].push_back(r);
	for (int i = 1; i < N; i++) {
		int v = p[i];
		vector<bool> f(N);
		int lo = 0, hi = N - 1;
		while (lo < hi) {
			int mi = (lo + hi + 1) / 2;
			bool ok = 0;
			for (int x : d[mi]) {
				if (dis[v] - dis[x] > 0 && dis[v] - dis[x] == get_distance(x + 1, v + 1)) {
					f[x] = 1;
					ok = 1;
					break;
				}
			}
			if (ok) {
				lo = mi;
			} else {
				hi = mi - 1;
			}
		}
		int u = -1;
		for (int x : d[lo]) {
			if (f[x]) {
				u = x;
			}
		}
		if (u == -1) {
			for (int x : d[lo]) {
				if (dis[v] - dis[x] > 0 && dis[v] - dis[x] == get_distance(x + 1, v + 1)) {
					u = x;
					break;
				}
			}
		}
		A[i - 1] = u + 1;
		B[i - 1] = v + 1;
		W[i - 1] = dis[v] - dis[u];
		d[lo + 1].push_back(v);
	}
}

Compilation message (stderr)

citymapping.cpp: In function 'void find_roads(int, int, int*, int*, int*)':
citymapping.cpp:21:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::tuple<long long int, int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   21 |   for (int i = 0; i < T.size(); i++) {
      |                   ~~^~~~~~~~~~

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