Code RoomMinimum road reversals to capital
MediumPrep Room Coding #1313

Minimum road reversals to capital

CodingAlgorithms & data structuresMid–Senior~25 min

There are n cities (0..n-1) connected by n-1 one-way roads forming a tree if you ignore direction. City 0 is the capital. Each road is given as `[a, b]` meaning a directed road from a to b. You can reverse the direction of any road. Return the minimum number of roads you must reverse so that every city can reach the capital (city 0). 1 <= n.

Implement
min_reorder_to_capital(n: int, connections: list[list[int]]) → int
Examples
in[6,[[0,1],[1,3],[2,3],[4,0],[4,5]]]out3
What a strong answer looks like

State your approach and its time/space complexity out loud before you optimize. Handle the edge cases (empty input, duplicates, overflow), and say why you chose this over the brute force. Green tests are the floor, not the grade.

0:00 of about 25 min
InputExpectedGot
[6,[[0,1],[1,3],[2,3],[4,0],[4,5]]]3not run yetsample