Create 04_leftLeavesSum.cpp

11 November Leetcode Challenge 2021/04_leftLeavesSum.cpp

@@ -0,0 +1,31 @@
+
+int sum;
+
+bool isLeaf(TreeNode* root){
+    return root && root->left == NULL && root->right == NULL;
+}
+
+
+void addLeft(TreeNode* root){
+
+    if (root == NULL)
+        return;
+
+    if (root->left != NULL){
+        if (isLeaf(root->left)){
+            sum += root->left->val;            
+        }               
+    }
+    addLeft(root->left);
+    addLeft(root->right);
+}
+
+class Solution {
+public:
+    int sumOfLeftLeaves(TreeNode* root){                
+        sum = 0;
+        addLeft(root);
+
+        return sum;
+    }
+};