62 lines
1.9 KiB
C++
62 lines
1.9 KiB
C++
#include <iostream>
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#include <vector>
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#include <cmath>
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#include <algorithm>
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using namespace std;
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double other_leg(const double leg, const double diag) {
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return sqrt(diag * diag - leg * leg);
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}
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double diag(const double leg1, const double leg2) {
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return sqrt(leg1 * leg1 + leg2 * leg2);
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}
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int required_radars(vector<pair<int, int>> islands, int distance) {
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for (auto& [island_x, island_y] : islands) {
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if (island_y > distance) { return -1; }
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}
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sort(islands.begin(), islands.end());
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int answer = 0;
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while (!islands.empty()) {
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answer++;
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const auto current_island = islands.back();
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islands.pop_back();
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double min_x = current_island.first
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- other_leg(current_island.second, distance)
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- current_island.second;
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vector<pair<int, int>> uncovered_islands;
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while (!islands.empty() && islands.back().first >= min_x) {
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// 右移雷达
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const double offset = other_leg(islands.back().second, distance);
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if (islands.back().first - offset >= min_x) {
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min_x = islands.back().first - offset;
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} else {
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uncovered_islands.push_back(islands.back());
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}
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islands.pop_back();
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}
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for (int i = uncovered_islands.size() - 1; i >= 0; i--) { // NOLINT(*-narrowing-conversions)
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islands.push_back(uncovered_islands[i]);
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}
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}
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return answer;
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}
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int main() {
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ios::sync_with_stdio(false);
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cin.tie(nullptr);
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int n, distance, case_id = 0;
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while (cin >> n >> distance) {
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if (n == 0 && distance == 0) { break; }
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vector<pair<int, int>> islands(n);
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for (int i = 0; i < n; i++) {
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cin >> islands[i].first >> islands[i].second;
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}
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cout << "Case " << ++case_id << ": " << required_radars(islands, distance) << endl;
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}
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}
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