Design Pattern 14: Top 'K' Elements | Problem: K Closest Points to Origin

14_k_closest_points_to_origin.cpp

@@ -0,0 +1,58 @@
+/* Problem: https://leetcode.com/problems/k-closest-points-to-origin/ */
+
+#include "lib_leetcode.h"
+#include <algorithm>
+#include <cmath>
+#include <iostream>
+#include <ostream>
+#include <vector>
+
+struct coord_dist {
+  int x;
+  int y;
+  double distance;
+  bool operator<(const coord_dist &other) const {
+    return distance < other.distance;
+  }
+};
+
+std::ostream &operator<<(std::ostream &out, const coord_dist &cd) {
+  out << "x: " << cd.x << "\ty: " << cd.y << "\tdistance: " << cd.distance;
+  return out;
+}
+
+std::ostream &operator<<(std::ostream &out, std::vector<coord_dist> &cd_vec) {
+  if (!cd_vec.size()) {
+    out << "{}";
+    return out;
+  }
+  out << "{\n";
+  for (const coord_dist &cd : cd_vec) {
+    out << '\t' << cd << ",\n";
+  }
+  out << "\b\b\n}";
+  return out;
+}
+
+std::vector<std::vector<int>> solution(std::vector<std::vector<int>> &&points,
+                                       int k) {
+  std::vector<coord_dist> distances;
+  for (const std::vector<int> &coordinates : points) {
+    int x = coordinates[0], y = coordinates[1];
+    double distance;
+    distance = std::sqrt(x * x + y * y);
+    distances.push_back({x, y, distance});
+  }
+  std::sort(distances.begin(), distances.end());
+  // std::cout << distances << '\n';
+  std::vector<std::vector<int>> kClosest;
+  for (int i = 0; i < k; i++)
+    kClosest.push_back({distances[i].x, distances[i].y});
+  return kClosest;
+}
+
+int main() {
+  std::cout << solution({{1, 3}, {-2, 2}}, 1) << '\n'
+            << solution({{3, 3}, {5, -1}, {-2, 4}}, 2) << '\n'
+            << solution({{-5, 4}, {-6, -5}, {4, 6}}, 2) << '\n';
+}

CMakeLists.txt

@@ -28,3 +28,5 @@ add_executable(10_find_the_median_of_a_number_stream 10_find_the_median_of_a_num
 add_executable(11_letter_case_permutation 11_letter_case_permutation.cpp)
 
 add_executable(11_permutations_in_string 11_permutations_in_string.cpp)
+
+add_executable(14_k_closest_points_to_origin 14_k_closest_points_to_origin.cpp)