0404_Sum_of_Left_Leaves.cpp

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
 *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 * };
 */

#pragma GCC optimize("Ofast","inline","ffast-math","unroll-loops","no-stack-protector")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native","f16c")
auto init = []()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    return 'c';
}();
class Solution {
public:

    int solve(TreeNode* root, bool tleft){
        if(root==NULL){
            return 0;
        }
        if(tleft && root->left==NULL && root->right==NULL){
            return root->val;
        }

        return solve(root->left, true) + solve(root->right, false);
    }

    int sumOfLeftLeaves(TreeNode* root) {
        return solve(root, false);
    }
};