1057. Campus Bikes

src/main/java/algorithms/curated170/medium/campusbikes/CampusBikesBucketSort.java

@@ -0,0 +1,94 @@
+package algorithms.curated170.medium;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+public class CampusBikesBucketSort {
+
+      int w, b;
+      List<int[]>[] buckets = new List[2001];
+
+      public int[] assignBikes(int[][] workers, int[][] bikes) {
+
+            w = workers.length;
+            b = bikes.length;
+
+            assignToBuckets(workers, bikes);
+
+            return assignFromBuckets();
+      }
+
+      private void assignToBuckets(int[][] workers, int[][] bikes) {
+            for (int i = 0; i < w; i++) {
+                  for (int j = 0; j < b; j++) {
+                        int dist = dist(workers[i], bikes[j]);
+                        if (buckets[dist] == null) {
+                              buckets[dist] = new ArrayList<>();
+                        }
+
+                        buckets[dist].add(new int[] { i, j });
+                  }
+            }
+      }
+
+      private int[] assignFromBuckets() {
+
+            int[] wo = new int[w];
+            boolean[] bikeAssigned = new boolean[b];
+            boolean[] workerAssigned = new boolean[w];
+            short assigned = 0;
+
+            for (int i = 0; i < buckets.length && assigned < w; i++) {
+                  if (buckets[i] != null) {
+                        for (int[] pair : buckets[i]) {
+
+                              int w_ = pair[0];
+                              int b_ = pair[1];
+
+                              if (!workerAssigned[w_] && !bikeAssigned[b_]) {
+                                    wo[w_] = b_;
+
+                                    bikeAssigned[b_] = true;
+                                    workerAssigned[w_] = true;
+                                    assigned++;
+                              }
+                        }
+                  }
+            }
+            return wo;
+      }
+
+      private int dist(int[] w, int[] b) {
+            return Math.abs(w[0] - b[0]) + Math.abs(w[1] - b[1]);
+      }
+
+      public static void main(String[] args) {
+            int[][] workers0 = {{664,994},{3,425},{599,913},{220,352},{145,348},{604,428},{519,183},{732,148}};
+
+            int[][] bikes0 = {{611,698},{113,338},{579,770},{276,588},{948,679},{731,525},{925,877},{182,281},{39,299}};
+
+
+            var solution = new CampusBikesBucketSort();
+            System.out.println(Arrays.toString(solution.assignBikes(workers0, bikes0)));
+            solution.printBuckets();
+      }
+
+      void printBuckets()
+      {
+            StringBuilder sb = new StringBuilder();
+            for(List<int[]> k : buckets)
+            {
+                  if(k==null)
+                  {
+                        continue;
+                  }
+                  for(int[] j : k)
+                  {
+                        sb.append(Arrays.toString(j));
+                  }
+                  sb.append("/");
+            }
+            System.out.println(sb.toString());
+      }
+}

src/main/java/algorithms/curated170/medium/campusbikes/CampusBikesPriorityQueue.java

@@ -0,0 +1,76 @@
+package algorithms.curated170.medium;
+
+import java.util.Arrays;
+import java.util.Comparator;
+import java.util.PriorityQueue;
+
+public class CampusBikesPriorityQueue {
+
+      int w, b;
+      PriorityQueue<int[]> pq = new PriorityQueue<>(new Comparator<int[]>() {
+            @Override
+            public int compare(int[] a, int[] b) {
+                  return a[0] != b[0] ? a[0] - b[0] : (a[1] != b[1] ? a[1] - b[1] : (a[2] - b[2]));
+            }
+      });
+
+      public int[] assignBikes(int[][] workers, int[][] bikes) {
+
+            w = workers.length;
+            b = bikes.length;
+
+            createHeap(workers, bikes);
+
+            return assignFromHeap();
+      }
+
+      private void createHeap(int[][] workers, int[][] bikes) {
+            for (int i = 0; i < w; i++) {
+                  for (int j = 0; j < b; j++) {
+
+                        int dist = dist(workers[i], bikes[j]);
+                        pq.offer(new int[] { dist, i, j });
+                  }
+            }
+      }
+
+      private int[] assignFromHeap() {
+
+            int[] wo = new int[w];
+
+            boolean[] bikeAssigned = new boolean[b];
+            boolean[] workerAssigned = new boolean[w];
+
+            int assigned = 0;
+            while (!pq.isEmpty() && assigned < w) {
+                  int[] entry = pq.poll();
+
+                  int w_ = entry[1];
+                  int b_ = entry[2];
+
+                  if (!workerAssigned[w_] && !bikeAssigned[b_]) {
+                        wo[w_] = b_;
+
+                        workerAssigned[w_] = true;
+                        bikeAssigned[b_] = true;
+                        assigned++;
+                  }
+            }
+
+            return wo;
+      }
+
+      private int dist(int[] w, int[] b) {
+            return Math.abs(w[0] - b[0]) + Math.abs(w[1] - b[1]);
+      }
+
+      public static void main(String[] args) {
+            int[][] workers0 = {{664,994},{3,425},{599,913},{220,352},{145,348},{604,428},{519,183},{732,148}};
+
+            int[][] bikes0 = {{611,698},{113,338},{579,770},{276,588},{948,679},{731,525},{925,877},{182,281},{39,299}};
+
+
+            var solution = new CampusBikesPriorityQueue();
+            System.out.println(Arrays.toString(solution.assignBikes(workers0, bikes0)));
+      }
+}