1719. Number Of Ways To Reconstruct A Tree

解題說明

C++ 解法

複雜度分析

虛擬碼

1. Build adjacency sets from pairs
2. Sort nodes by degree descending
3. If root (highest degree) does not have degree n-1, return 0
4. For each node v (in sorted order):
   a. Find parent = neighbor with smallest degree >= deg(v)
   b. If no parent found and v is not root, return 0
   c. Check all neighbors of v (except parent) are also neighbors of parent
   d. If check fails, return 0
   e. If parent has same degree as v, mark multipleWays = true
5. Return 2 if multipleWays, else 1

其他解法

延伸思考