Merge pull request #4 from princeghoshc7/Medium

Medium_coding_challenges

Author: princeghoshc7

DailyCodingProblem/src/Medium/WebsiteSimilarity.java

@@ -0,0 +1,72 @@
+package Medium;
+import java.util.*;
+
+public class WebsiteSimilarity {
+    public static void main(String[] args) {
+        List<Pair<String, Integer>> userVisits = Arrays.asList(
+                new Pair<>("a", 1), new Pair<>("a", 3), new Pair<>("a", 5),
+                new Pair<>("b", 2), new Pair<>("b", 6),
+                new Pair<>("c", 1), new Pair<>("c", 2), new Pair<>("c", 3),
+                new Pair<>("c", 4), new Pair<>("c", 5),
+                new Pair<>("d", 4), new Pair<>("d", 5), new Pair<>("d", 6), new Pair<>("d", 7),
+                new Pair<>("e", 1), new Pair<>("e", 3), new Pair<>("e", 5), new Pair<>("e", 6)
+        );
+
+        int k = 1; // You can change this to the desired value
+
+        Map<Integer, Set<String>> websiteUserMap = new HashMap<>();
+
+        // Build a map of websites to the set of users who visited them
+        for (Pair<String, Integer> visit : userVisits) {
+            websiteUserMap.computeIfAbsent(visit.getSecond(), key -> new HashSet<>()).add(visit.getFirst());
+        }
+
+        List<Pair<String, String>> websitePairs = new ArrayList<>();
+
+        // Calculate the similarity between website pairs
+        for (String user1 : websiteUserMap.get(1)) {
+            for (String user2 : websiteUserMap.get(1)) {
+                if (!user1.equals(user2)) {
+                    Set<String> commonWebsites = new HashSet<>(websiteUserMap.get(1));
+                    commonWebsites.retainAll(websiteUserMap.get(1));
+
+                    double similarity = (double) commonWebsites.size() / (websiteUserMap.get(1).size() + websiteUserMap.get(1).size() - commonWebsites.size());
+
+                    websitePairs.add(new Pair<>(user1, user2));
+                }
+            }
+        }
+
+        // Sort the website pairs by similarity and get the top k
+        websitePairs.sort((pair1, pair2) -> Double.compare(calculateSimilarity(pair2, websiteUserMap), calculateSimilarity(pair1, websiteUserMap)));
+
+        for (int i = 0; i < Math.min(k, websitePairs.size()); i++) {
+            System.out.println("Website Pair: " + websitePairs.get(i).getFirst() + ", " + websitePairs.get(i).getSecond());
+        }
+    }
+
+    private static double calculateSimilarity(Pair<String, String> websitePair, Map<Integer, Set<String>> websiteUserMap) {
+        Set<String> commonWebsites = new HashSet<>(websiteUserMap.get(1));
+        commonWebsites.retainAll(websiteUserMap.get(1));
+
+        return (double) commonWebsites.size() / (websiteUserMap.get(1).size() + websiteUserMap.get(1).size() - commonWebsites.size());
+    }
+
+    static class Pair<F, S> {
+        private final F first;
+        private final S second;
+
+        public Pair(F first, S second) {
+            this.first = first;
+            this.second = second;
+        }
+
+        public F getFirst() {
+            return first;
+        }
+
+        public S getSecond() {
+            return second;
+        }
+    }
+}