Added solution for N-Robots-Collisions problem

Author: NilayBadjatya

src/main/java/com/thealgorithms/simulation/NRobotsCollision.java

@@ -0,0 +1,26 @@
+package com.thealgorithms.simulation;
+
+public class NRobotsCollision {
+    static class Pair {
+        int first;
+        char second;
+        Pair(int first, char second) {
+            this.first = first;
+            this.second = second;
+        }
+    }
+    public static int earliestCollisionTime(int n, int[] positions, String directions) {
+        List<Pair> sortedDirections = new ArrayList<>();
+        for(int i = 0; i < n; i++){
+            sortedDirections.add(new Pair(positions[i], directions.charAt(i)));
+        }
+        sortedDirections.sort((a, b) -> Integer.compare(a.first, b.first));
+        int minTime = Integer.MAX_VALUE;
+        for(int i = 1; i < n; i++){
+            if(sortedDirections.get(i).second == 'L' && sortedDirections.get(i - 1).second == 'R'){
+                minTime = Math.min(minTime, sortedDirections.get(i).first - sortedDirections.get(i - 1).first);
+            }
+        }
+        return minTime == Integer.MAX_VALUE ? -1 : minTime / 2;
+    }
+}