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| class Solution {
public int sumRootToLeaf(TreeNode root) {
return dfs(root, 0);
}
private int dfs(TreeNode root, int prefix) {
if (root == null) {
return 0;
}
prefix = (prefix << 1) + root.val;
if (root.left == null && root.right == null) {
return prefix;
}
return dfs(root.left, prefix) + dfs(root.right, prefix);
}
}
|
References
1022. Sum of Root To Leaf Binary Numbers