solved Traffic Lights

Author: nteshxx

Sorting and Searching/java/TrafficLights.java

@@ -0,0 +1,65 @@
+import java.io.BufferedOutputStream;
+import java.io.IOException;
+import java.util.List;
+import java.util.NavigableSet;
+import java.util.Scanner;
+import java.util.TreeMap;
+import java.util.TreeSet;
+
+public class TrafficLights {
+    
+    public static void main(String[] args) throws IOException {
+
+        // reader
+        Scanner sc = new Scanner(System.in);
+
+        // inputs
+        int streetLength = sc.nextInt();
+        int numberOfTrafficLights = sc.nextInt();
+        sc.nextLine();
+
+        String[] positionOfTrafficLights = sc.nextLine().split("\\s+");
+
+        // writer
+        BufferedOutputStream writer = new BufferedOutputStream(System.out);
+
+        // solve
+        NavigableSet<Integer> street = new TreeSet<>(List.of(0, streetLength));
+        TreeMap<Integer, Integer> passages = new TreeMap<>();
+
+        for (int i = 0; i < numberOfTrafficLights; i++) {
+            Integer trafficLightPosition = Integer.parseInt(positionOfTrafficLights[i]);
+
+            Integer nextLightPositon = street.higher(trafficLightPosition);
+            Integer previousLightPosition = nextLightPositon != null ? street.lower(nextLightPositon) : null;
+
+            if (previousLightPosition != null && nextLightPositon != null) {
+                Integer passageToBeDivided = nextLightPositon - previousLightPosition;
+                Integer leftDivision = trafficLightPosition - previousLightPosition;
+                Integer rightDivision = nextLightPositon - trafficLightPosition;
+
+                passages.put(passageToBeDivided, passages.getOrDefault(passageToBeDivided, 1) - 1);
+                if (passages.getOrDefault(passageToBeDivided, 0) == 0) {
+                    passages.remove(passageToBeDivided);
+                }
+
+                passages.put(leftDivision, passages.getOrDefault(leftDivision, 0) + 1);
+                passages.put(rightDivision, passages.getOrDefault(rightDivision, 0) + 1);
+            }
+
+            street.add(trafficLightPosition);
+
+            writer.write((passages.lastKey() + " ").getBytes());
+
+        }
+
+        writer.flush();
+
+        // close reader
+        sc.close();
+        
+        return;
+
+    }
+
+}