body of graph valid tree

fishercoder1534 · fishercoder1534 · commit f0798d108cec · 2016-09-29T21:27:37.000-07:00
diff --git a/MEDIUM/src/medium/GraphValidTree.java b/MEDIUM/src/medium/GraphValidTree.java
@@ -1,7 +1,31 @@
 package medium;
 
+import java.util.Arrays;
+
 /**
  * Created by fishercoder1534 on 9/29/16.
  */
 public class GraphValidTree {
+
+    public boolean validTree(int n, int[][] edges){
+        int[] nums = new int[n];
+        Arrays.fill(nums, -1);
+
+        for(int i = 0; i < edges.length; i++){
+            int x = find(nums, edges[i][0]);
+            int y = find(nums, edges[i][1]);
+
+            if(x == y) return false;
+
+            //union
+            nums[x] = y;
+        }
+
+        return edges.length == n-1;
+    }
+
+    int find(int[] nums, int i){
+        if(nums[i] == -1) return i;
+        return find(nums, nums[i]);
+    }
 }
