update: 2 solutions

Author: hijiangtao

README.md

@@ -2,13 +2,14 @@
 
 This is the solution collection of my LeetCode problems, most of them are programmed in JavaScript.
 
-Progress: 12/
+Progress: 14/
 
 | ID | Title | Solution | Difficulty |
 |---| ----- | -------- | ---------- |
 |1|[Two Sum](https://leetcode.com/problems/two-sum/) | [JavaScript](./src/two-sum/res.js)|Easy|
 |2|[Add Two Numbers](https://leetcode.com/problems/add-two-numbers/) | [JavaScript](./src/add-two-numbers/res.js)|Medium|
 |66|[Plus One](https://leetcode.com/problems/plus-one/) | [JavaScript](./src/plus-one/res.js)|Easy|
+|69|[Sqrt(x)](https://leetcode.com/problems/sqrtx/) | [JavaScript](./src/sqrtx/res.js)|Easy|
 |175|[Combine Two Tables](https://leetcode.com/problems/combine-two-tables/)| [SQL](./src/combine-two-tables/res.txt)|Easy|
 |176|[Second Highest Salary](https://leetcode.com/problems/second-highest-salary/)| [SQL](./src/second-highest-salary/res.txt)|Easy|
 |177|[Nth Highest Salary](https://leetcode.com/problems/nth-highest-salary/)| [SQL](./src/nth-highest-salary/res.txt)|Medium|
@@ -17,4 +18,5 @@ Progress: 12/
 |184|[Department Highest Salary](https://leetcode.com/problems/department-highest-salary/) | [SQL](./src/department-highest-salary/res.txt)|Medium|
 |197|[Rising Temperature](https://leetcode.com/problems/rising-temperature/) | [SQL](./src/rising-temperature/res.txt)|Easy|
 |342|[Power of Four](https://leetcode.com/problems/power-of-four/) | [JavaScript](./src/power-of-four/res.js)|Easy|
+|404|[Sum of Left Leaves](https://leetcode.com/problems/sum-of-left-leaves/) | [JavaScript](./src/sum-of-left-leaves/res.js)|Easy|
 |434|[Number of Segments in a String](https://leetcode.com/problems/number-of-segments-in-a-string/) | [JavaScript](./src/number-of-segments-in-a-string/res.js)|Easy|

src/sqrtx/res.js

@@ -0,0 +1,55 @@
+/**
+ * res.js
+ * @authors Joe Jiang (hijiangtao@gmail.com)
+ * @date    2017-02-19 10:53:04
+ * @version $Id$
+ */
+
+/**
+ * @param {number} x
+ * @return {number}
+ */
+let mySqrt = function(x) {
+	if (x === 1 || x === 0) {
+		return x;
+	} else if (x < 0) {
+		return 0;
+	}
+
+	let i = 1;
+	for (;; i += 2) {
+		if (i*(i+1) >= x) {
+			break;
+		}
+	}
+
+	for (;; i--) {
+		if (i*i <= x) {
+			return i;
+		}
+	}
+};
+
+// Another solution
+let mySqrt = function(x) {
+	if (x === 1 || x === 0) {
+		return x;
+	} else if (x < 0) {
+		return 0;
+	}
+
+	let min = 1, max = x+1;
+	while (true) {
+		let mid = min + Number.parseInt((max-min)/2);
+
+		if (mid*mid > x) {
+			max = mid-1;
+		} else {
+			if ((mid+1)*(mid+1) > x) {
+				return mid;
+			} else {
+				min = mid+1;
+			}
+		}
+	}
+};

src/sum-of-left-leaves/res.js

@@ -0,0 +1,55 @@
+// Find the sum of all left leaves in a given binary tree.
+
+// Example:
+
+//     3
+//    / \
+//   9  20
+//     /  \
+//    15   7
+
+// There are two left leaves in the binary tree, with values 9 and 15 respectively. Return 24.
+
+/**
+ * res.js
+ * @authors Joe Jiang (hijiangtao@gmail.com)
+ * @date    2017-02-19 10:13:41
+ * @version $Id$
+ */
+
+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val) {
+ *     this.val = val;
+ *     this.left = this.right = null;
+ * }
+ */
+/**
+ * @param {TreeNode} root
+ * @return {number}
+ */
+let sumOfLeftLeaves = function(root) {
+    // Deal with the first root value
+    if (!root || root.val===null || (!root.left && !root.right)) {
+    	return 0;
+    }
+
+    let leftlefVal = 0, rightlefVal = 0;
+    if (root.left) {
+    	if (!root.left.left && !root.left.right) {
+    		leftlefVal = root.left.val;
+    	} else {
+    		leftlefVal = sumOfLeftLeaves(root.left);
+    	}
+    }
+
+    if (root.right) {
+    	if (!root.right.left && !root.right.right) {
+    		rightlefVal = 0;
+    	} else {
+    		rightlefVal = sumOfLeftLeaves(root.right);
+    	}
+    }
+
+    return leftlefVal + rightlefVal;
+};