add 783

Author: fishercoder1534

README.md

@@ -22,6 +22,7 @@ Your ideas/fixes/algorithms are more than welcome!
 
 |  #  |      Title     |   Solutions   | Time          | Space         | Video  | Difficulty  | Tag                   
 |-----|----------------|---------------|---------------|---------------|--------|-------------|-------------
+|783|[Minimum Distance Between BST Nodes](https://leetcode.com/problems/minimum-distance-between-bst-nodes/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_783.java) | O(n) | O(h) | |Easy|
 |779|[K-th Symbol in Grammar](https://leetcode.com/problems/k-th-symbol-in-grammar/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_779.java) | O(logn) | O(1) | |Medium|
 |776|[Split BST](https://leetcode.com/problems/split-bst/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_776.java) | O(n) | O(n) | |Medium| Recursion
 |771|[Jewels and Stones](https://leetcode.com/problems/jewels-and-stones/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_771.java) | O(n) | O(m) | |Easy|

src/main/java/com/fishercoder/solutions/_783.java

@@ -0,0 +1,60 @@
+package com.fishercoder.solutions;
+
+import com.fishercoder.common.classes.TreeNode;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * 783. Minimum Distance Between BST Nodes
+ *
+ * Given a Binary Search Tree (BST) with the root node root, return the minimum difference between the values of any two different nodes in the tree.
+
+ Example :
+
+ Input: root = [4,2,6,1,3,null,null]
+ Output: 1
+ Explanation:
+ Note that root is a TreeNode object, not an array.
+
+ The given tree [4,2,6,1,3,null,null] is represented by the following diagram:
+
+      4
+    /   \
+   2     6
+  / \
+ 1  3
+
+ while the minimum difference in this tree is 1, it occurs between node 1 and node 2, also between node 3 and node 2.
+
+ Note:
+
+ The size of the BST will be between 2 and 100.
+ The BST is always valid, each node's value is an integer, and each node's value is different.
+ */
+
+public class _783 {
+  public static class Solution1 {
+    public int minDiffInBST(TreeNode root) {
+      List<Integer> inorder = new ArrayList<>();
+      inorder(root, inorder);
+      return findMinDiff(inorder);
+    }
+
+    private int findMinDiff(List<Integer> inorder) {
+      int minDiff = Integer.MAX_VALUE;
+      for (int i = 1; i < inorder.size(); i++) {
+        minDiff = Math.min(minDiff, inorder.get(i) - inorder.get(i - 1));
+      }
+      return minDiff;
+    }
+
+    private void inorder(TreeNode root, List<Integer> inorder) {
+      if (root == null) {
+        return;
+      }
+      inorder(root.left, inorder);
+      inorder.add(root.val);
+      inorder(root.right, inorder);
+    }
+  }
+}

src/test/java/com/fishercoder/_783Test.java

@@ -0,0 +1,27 @@
+package com.fishercoder;
+
+import com.fishercoder.common.classes.TreeNode;
+import com.fishercoder.common.utils.TreeUtils;
+import com.fishercoder.solutions._783;
+import java.util.Arrays;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class _783Test {
+  private static _783.Solution1 solution1;
+  private static TreeNode root;
+
+  @BeforeClass
+  public static void setup() {
+    solution1 = new _783.Solution1();
+  }
+
+  @Test
+  public void test1() {
+    root = TreeUtils.constructBinaryTree(Arrays.asList(4, 2, 6, 1, 3, null, null));
+    TreeUtils.printBinaryTree(root);
+    assertEquals(1, solution1.minDiffInBST(root));
+  }
+}