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// 404. Sum of Left Leaves
#include "leetcode.h"
/*
* given the 'root' of a binary tree, return the sum of all left leaves. a leaf
* is a node with no childen. a leaft leaf is a leaf that is the left child of
* another node.
*/
struct TreeNode {
int val;
struct TreeNode *left;
struct TreeNode *right;
};
struct TreeNode *createNode(int val) {
struct TreeNode *new_node =
(struct TreeNode *)malloc(sizeof(struct TreeNode));
new_node->val = val;
new_node->left = NULL;
new_node->right = NULL;
return new_node;
}
void dfs(struct TreeNode *node, int *sum, bool left) {
if (!node)
return;
if (!node->left && !node->right && left) {
(*sum) += node->val;
return;
}
dfs(node->left, sum, 1);
dfs(node->right, sum, 0);
}
int sumOfLeftLeaves(struct TreeNode *root) {
int sum = 0;
dfs(root, &sum, 0);
return sum;
}
int main() {
struct TreeNode *root = createNode(3);
root->left = createNode(9);
root->right = createNode(20);
root->right->left = createNode(15);
root->right->right = createNode(7);
printf("%d\n", sumOfLeftLeaves(root)); // expect: 24
free(root);
}
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