問題
In a directed graph with nodes 0..n−1, a strongly connected component is a maximal group of nodes where every node can reach every other. Count the components (Kosaraju's or Tarjan's algorithm).
Implement count_scc(n, edges).
Input
n: The number of nodes. edges: Directed edges as [from, to].
Output
Return the number of components.
制約
1 ≤ n ≤ 100,000; 0 ≤ edges ≤ 200,000
例
例 1
入力：
n = 5
edges = [
[0, 1],
[1, 2],
[2, 0],
[3, 4]
]
期待される出力：
expected = 3入力：
long long n = 5;
std::vector<std::vector<long long>> edges = {
{0, 1},
{1, 2},
{2, 0},
{3, 4}
};
期待される出力：
long long expected = 3;入力：
long n = 5;
long[][] edges = new long[][] {
new long[] {0, 1},
new long[] {1, 2},
new long[] {2, 0},
new long[] {3, 4}
};
期待される出力：
long expected = 3;解説
0, 1, 2 form a cycle (one component); 3 and 4 can't reach each other, so they are separate: 3.
例 2
入力：
n = 3
edges = [
[0, 1],
[1, 0],
[1, 2],
[2, 1]
]
期待される出力：
expected = 1入力：
long long n = 3;
std::vector<std::vector<long long>> edges = {
{0, 1},
{1, 0},
{1, 2},
{2, 1}
};
期待される出力：
long long expected = 1;入力：
long n = 3;
long[][] edges = new long[][] {
new long[] {0, 1},
new long[] {1, 0},
new long[] {1, 2},
new long[] {2, 1}
};
期待される出力：
long expected = 1;解説
All three nodes reach each other: 1.
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。