Update 547_Number_of_Provinces.java

Author: seanprashad

Graphs/47_Number_of_Provinces.java

@@ -0,0 +1,58 @@
+class Solution {
+    public int findCircleNum(int[][] isConnected) {
+        UnionFind uf = new UnionFind(isConnected.length);
+
+        for (int row = 0; row < isConnected.length; row++) {
+            for (int col = 0; col < isConnected[row].length; col++) {
+                if (isConnected[row][col] == 1) {
+                    uf.union(row, col);
+                }
+            }
+        }
+
+        return uf.noOfComponents;
+    }
+
+    private class UnionFind {
+        private int[] parents, counts;
+        private int noOfComponents;
+
+        public UnionFind(int n) {
+            noOfComponents = n;
+            parents = new int[n];
+            counts = new int[n];
+
+            for (int i = 0; i < parents.length; i++) {
+                parents[i] = i;
+                counts[i] = 1;
+            }
+        }
+
+        public int find(int node) {
+            if (parents[node] == node) {
+                return node;
+            }
+
+            parents[node] = find(parents[parents[node]]);
+            return parents[node];
+        }
+
+        public void union(int i, int j) {
+            int p1 = find(i), p2 = find(j);
+
+            if (p1 == p2) {
+                return;
+            }
+
+            if (counts[p1] > counts[p2]) {
+                parents[p2] = p1;
+                counts[p1] += counts[p2];
+            } else {
+                parents[p1] = p2;
+                counts[p2] += counts[p1];
+            }
+
+            --noOfComponents;
+        }
+    }
+}