Create 0988-smallest-string-starting-from-leaf.js

Author: aadil42

javascript/0988-smallest-string-starting-from-leaf.js

@@ -0,0 +1,53 @@
+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val, left, right) {
+ *     this.val = (val===undefined ? 0 : val)
+ *     this.left = (left===undefined ? null : left)
+ *     this.right = (right===undefined ? null : right)
+ * }
+ */
+/**
+ * Tree | Backtracking
+ * Time O(n^2) | Space O(n)
+ * https://leetcode.com/problems/smallest-string-starting-from-leaf/
+ * @param {TreeNode} root
+ * @return {string}
+ */
+var smallestFromLeaf = function(root) {
+
+    let biggestStr = new Array(8500).fill("z");
+    biggestStr = biggestStr.join("");
+
+    let smallest = biggestStr;
+    const dfs = (node, str) => {
+
+        const char = String.fromCharCode(node.val+97);
+
+        if(!node.left && !node.right) {
+            str.push(char);
+            const str1 = str.slice(0).reverse().join("");
+            if(str1 < smallest) {
+                smallest = str1;
+            }
+            str.pop();
+            return;
+
+        }
+
+        if(node.left) {
+            str.push(char);
+            dfs(node.left, str);
+            str.pop();
+        }
+
+        if(node.right) {
+            str.push(char);
+            dfs(node.right, str);
+            str.pop();
+        }        
+    }
+
+    dfs(root,[]);
+
+    return smallest;
+};