問題
Tasks 0..n−1 form a directed acyclic graph. Each edge [u, v, w] means task v can start w hours after task u. Find the length of the longest path (the critical path). Process nodes in topological order.
Implement longest_path(n, edges).
Input
n: The number of nodes. edges: Edges as [from, to, weight].
Output
Return the total weight of the longest path (0 if there are no edges).
制約
1 ≤ n ≤ 100,000; 0 ≤ edges ≤ 200,000; 1 ≤ weight ≤ 10,000; the graph has no cycles
例
例 1
入力：
n = 4
edges = [
[0, 1, 3],
[0, 2, 2],
[1, 3, 4],
[2, 3, 6]
]
期待される出力：
expected = 8入力：
long long n = 4;
std::vector<std::vector<long long>> edges = {
{0, 1, 3},
{0, 2, 2},
{1, 3, 4},
{2, 3, 6}
};
期待される出力：
long long expected = 8;入力：
long n = 4;
long[][] edges = new long[][] {
new long[] {0, 1, 3},
new long[] {0, 2, 2},
new long[] {1, 3, 4},
new long[] {2, 3, 6}
};
期待される出力：
long expected = 8;解説
0→1→3 weighs 7, 0→2→3 weighs 8: the longest path is 8.
例 2
入力：
n = 3
edges = []
期待される出力：
expected = 0入力：
long long n = 3;
std::vector<std::vector<long long>> edges = {};
期待される出力：
long long expected = 0;入力：
long n = 3;
long[][] edges = new long[][] {};
期待される出力：
long expected = 0;解説
Without edges every path has length 0.
参考資料
この課題はCodeUtility用に調整されています。上記の説明と制約に従ってください。