338. Familystrokes [ 2026 Release ]

while stack: v, p = stack.pop() child_cnt = 0 for w in g[v]: if w == p: continue child_cnt += 1 stack.append((w, v)) if child_cnt: internal += 1 if child_cnt >= 2: horizontal += 1

Both bounds comfortably meet the limits for N ≤ 10⁵ . Below are clean, self‑contained implementations in C++17 and Python 3 that follow the algorithm exactly. 6.1 C++17 #include <bits/stdc++.h> using namespace std; 338. FamilyStrokes

root = 1 stack = [(root, 0)] # (node, parent) internal = 0 horizontal = 0 while stack: v, p = stack

Only‑if childCnt = 1 : the sole child is placed directly under the parent; the horizontal segment would have length zero and is omitted by the drawing convention. ∎ The number of strokes contributed by a node v is ∎ The number of strokes contributed by a

internalCnt ← 0 // |I| horizontalCnt ← 0 // # v