add new solutions

solutions/1/q112/solution.go

@@ -0,0 +1,26 @@
+package q112
+
+type TreeNode struct {
+	Val   int
+	Left  *TreeNode
+	Right *TreeNode
+}
+
+func traverse(node *TreeNode, tgtSum, curSum int) bool {
+	if node == nil {
+		return false
+	}
+
+	sum := curSum + node.Val
+	if node.Left == nil && node.Right == nil && sum == tgtSum {
+		return true
+	}
+	return traverse(node.Left, tgtSum, sum) ||
+		traverse(node.Right, tgtSum, sum)
+}
+
+func hasPathSum(root *TreeNode, targetSum int) bool {
+	return traverse(root, targetSum, 0)
+}
+
+var _ = hasPathSum