| 87 | |
| 88 | // 迭代版 |
| 89 | public static void tarjan2(int node) { |
| 90 | stacksize = 0; |
| 91 | push(node, -1, -1); |
| 92 | int v; |
| 93 | while (stacksize > 0) { |
| 94 | pop(); |
| 95 | if (status == -1) { |
| 96 | dfn[u] = low[u] = ++cntd; |
| 97 | sta[++top] = u; |
| 98 | e = head[u]; |
| 99 | } else { |
| 100 | v = to[e]; |
| 101 | if (status == 0) { |
| 102 | low[u] = Math.min(low[u], low[v]); |
| 103 | } |
| 104 | if (status == 1 && belong[v] == 0) { |
| 105 | low[u] = Math.min(low[u], dfn[v]); |
| 106 | } |
| 107 | e = nxt[e]; |
| 108 | } |
| 109 | if (e != 0) { |
| 110 | v = to[e]; |
| 111 | if (dfn[v] == 0) { |
| 112 | push(u, 0, e); |
| 113 | push(v, -1, -1); |
| 114 | } else { |
| 115 | push(u, 1, e); |
| 116 | } |
| 117 | } else { |
| 118 | if (dfn[u] == low[u]) { |
| 119 | sccCnt++; |
| 120 | int pop; |
| 121 | do { |
| 122 | pop = sta[top--]; |
| 123 | belong[pop] = sccCnt; |
| 124 | } while (pop != u); |
| 125 | } |
| 126 | } |
| 127 | } |
| 128 | } |
| 129 | |
| 130 | public static void main(String[] args) throws Exception { |
| 131 | FastReader in = new FastReader(System.in); |