2025-01-09 20:29:41 +08:00
< p > Given the < code > root< / code > of a binary tree, replace the value of each node in the tree with the < strong > sum of all its cousins' values< / strong > .< / p >
< p > Two nodes of a binary tree are < strong > cousins< / strong > if they have the same depth with different parents.< / p >
< p > Return < em > the < / em > < code > root< / code > < em > of the modified tree< / em > .< / p >
< p > < strong > Note< / strong > that the depth of a node is the number of edges in the path from the root node to it.< / p >
< p > < / p >
< p > < strong class = "example" > Example 1:< / strong > < / p >
< img alt = "" src = "https://assets.leetcode.com/uploads/2023/01/11/example11.png" style = "width: 571px; height: 151px;" / >
< pre >
< strong > Input:< / strong > root = [5,4,9,1,10,null,7]
< strong > Output:< / strong > [0,0,0,7,7,null,11]
< strong > Explanation:< / strong > The diagram above shows the initial binary tree and the binary tree after changing the value of each node.
- Node with value 5 does not have any cousins so its sum is 0.
- Node with value 4 does not have any cousins so its sum is 0.
- Node with value 9 does not have any cousins so its sum is 0.
- Node with value 1 has a cousin with value 7 so its sum is 7.
- Node with value 10 has a cousin with value 7 so its sum is 7.
- Node with value 7 has cousins with values 1 and 10 so its sum is 11.
< / pre >
< p > < strong class = "example" > Example 2:< / strong > < / p >
< img alt = "" src = "https://assets.leetcode.com/uploads/2023/01/11/diagram33.png" style = "width: 481px; height: 91px;" / >
< pre >
< strong > Input:< / strong > root = [3,1,2]
< strong > Output:< / strong > [0,0,0]
< strong > Explanation:< / strong > The diagram above shows the initial binary tree and the binary tree after changing the value of each node.
- Node with value 3 does not have any cousins so its sum is 0.
- Node with value 1 does not have any cousins so its sum is 0.
- Node with value 2 does not have any cousins so its sum is 0.
< / pre >
< p > < / p >
< p > < strong > Constraints:< / strong > < / p >
< ul >
< li > The number of nodes in the tree is in the range < code > [1, 10< sup > 5< / sup > ]< / code > .< / li >
< li > < code > 1 < = Node.val < = 10< sup > 4< / sup > < / code > < / li >
< / ul >
