add 701

fishercoder1534 · fishercoder1534 · commit ca5fd5f8f5a3 · 2019-01-06T06:59:51.000-08:00
diff --git a/README.md b/README.md
@@ -115,6 +115,7 @@ Your ideas/fixes/algorithms are more than welcome!
 |706|[Design HashMap](https://leetcode.com/problems/design-hashmap/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_706.java) | O(n) | O(n) | |Easy| Design
 |705|[Design HashSet](https://leetcode.com/problems/design-hashset/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_705.java) | O(1) | O(n) | |Easy| Design
 |704|[Binary Search](https://leetcode.com/problems/binary-search/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_704.java) | O(logn) | O(1) | |Easy| Binary Search
+|701|[Insert into a Binary Search Tree](https://leetcode.com/problems/insert-into-a-binary-search-tree/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_701.java) | O(n) | O(h) | |Medium | DFS, recursion
 |700|[Search in a Binary Search Tree](https://leetcode.com/problems/search-in-a-binary-search-tree/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_700.java) | O(n) | O(h) | |Easy| recusion, dfs
 |699|[Falling Squares](https://leetcode.com/problems/falling-squares/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_699.java) | O(n^2) | O(n) | |Hard | Segment Tree
 |698|[Partition to K Equal Sum Subsets](https://leetcode.com/problems/partition-to-k-equal-sum-subsets/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_698.java) | O(n*(2^n)) | O(2^n) | |Medium | Backtracking
diff --git a/src/main/java/com/fishercoder/solutions/_701.java b/src/main/java/com/fishercoder/solutions/_701.java
@@ -0,0 +1,53 @@
+package com.fishercoder.solutions;
+
+import com.fishercoder.common.classes.TreeNode;
+
+/**
+ * 701. Insert into a Binary Search Tree
+ *
+ * Given the root node of a binary search tree (BST) and a value to be inserted into the tree, insert the value into the BST. Return the root node of the BST after the insertion. It is guaranteed that the new value does not exist in the original BST.
+ * Note that there may exist multiple valid ways for the insertion, as long as the tree remains a BST after insertion. You can return any of them.
+ *
+ * For example,
+ *
+ * Given the tree:
+ *         4
+ *        / \
+ *       2   7
+ *      / \
+ *     1   3
+ * And the value to insert: 5
+ *
+ *  You can return this binary search tree:
+ *
+ *          4
+ *        /   \
+ *       2     7
+ *      / \   /
+ *     1   3 5
+ *
+ * This tree is also valid:
+ *
+ *          5
+ *        /   \
+ *       2     7
+ *      / \
+ *     1   3
+ *          \
+ *           4
+ */
+public class _701 {
+  public static class Solution1 {
+    public TreeNode insertIntoBST(TreeNode root, int val) {
+      if (root == null) {
+        return new TreeNode(val);
+      }
+      if (root.val < val) {
+        root.right = insertIntoBST(root.right, val);
+      } else {
+        root.left = insertIntoBST(root.left, val);
+      }
+      return root;
+    }
+  }
+}
