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package leetcode.medium;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.PriorityQueue;
public class P_1057 {
// Bucket Sort
public int[] assignBikes(int[][] workers, int[][] bikes) {
final Map<Integer, List<int[]>> buckets = new HashMap<>();
final boolean[] bikeVisited = new boolean[bikes.length];
final int[] result = new int[workers.length];
Arrays.fill(result, -1);
for (int i = 0; i < workers.length; i++) {
for (int j = 0; j < bikes.length; j++) {
final int dist = Math.abs(workers[i][0] - bikes[j][0]) + Math.abs(workers[i][1] - bikes[j][1]);
buckets.computeIfAbsent(dist, v -> new ArrayList<>()).add(new int[] { i, j });
}
}
for (int k = 0; k <= 2000; k++) {
for (int[] arr : buckets.getOrDefault(k, Collections.emptyList())) {
final int w = arr[0];
final int b = arr[1];
if (result[w] == -1 && !bikeVisited[b]) {
result[w] = b;
bikeVisited[b] = true;
}
}
}
return result;
}
// Priority Queue
public int[] assignBikesPQ(int[][] workers, int[][] bikes) {
final boolean[] visited = new boolean[bikes.length];
final int[] res = new int[workers.length];
Arrays.fill(res, -1);
int count = 0;
final PriorityQueue<int[]> q = new PriorityQueue<>((a, b) -> {
if (a[0] == b[0] && a[1] == b[1]) {
return Integer.compare(a[2], b[2]);
}
if (a[0] == b[0]) {
return Integer.compare(a[1], b[1]);
}
return Integer.compare(a[0], b[0]);
});
for (int i = 0; i < workers.length; i++) {
for (int j = 0; j < bikes.length; j++) {
final int dist = Math.abs(bikes[j][0] - workers[i][0]) + Math.abs(bikes[j][1] - workers[i][1]);
q.add(new int[] { dist, i, j });
}
}
while (count < workers.length) {
final int[] curr = q.remove();
if (res[curr[1]] == -1 && !visited[curr[2]]) {
res[curr[1]] = curr[2];
visited[curr[2]] = true;
count++;
}
}
return res;
}
// Lazy Priority Queue
public int[] assignBikesPQLazy(int[][] workers, int[][] bikes) {
final boolean[] visited = new boolean[bikes.length];
final int[] res = new int[workers.length];
int count = 0;
final PriorityQueue<int[]> q = new PriorityQueue<>((a, b) -> {
if (a[0] == b[0] && a[1] == b[1]) {
return Integer.compare(a[2], b[2]);
}
if (a[0] == b[0]) {
return Integer.compare(a[1], b[1]);
}
return Integer.compare(a[0], b[0]);
});
for (int i = 0; i < workers.length; i++) {
q.offer(helper(workers, i, bikes, visited));
}
while (!q.isEmpty() && count < workers.length) {
final int[] curr = q.poll();
if (visited[curr[2]]) {
q.offer(helper(workers, curr[1], bikes, visited));
} else {
res[curr[1]] = curr[2];
visited[curr[2]] = true;
count++;
}
}
return res;
}
private static int[] helper(int[][] workers, int i, int[][] bikes, boolean[] visited) {
int min = Integer.MAX_VALUE, indexJ = -1;
for (int j = 0; j < bikes.length; j++) {
if (!visited[j]) {
final int dist = Math.abs(bikes[j][0] - workers[i][0]) + Math.abs(bikes[j][1] - workers[i][1]);
if (dist < min) {
min = dist;
indexJ = j;
}
}
}
return new int[] { min, i, indexJ };
}
}