| 109 | |
| 110 | // 迭代版 |
| 111 | public static void tarjan2(int node) { |
| 112 | stacksize = 0; |
| 113 | push(node, -1, -1); |
| 114 | int v; |
| 115 | while (stacksize > 0) { |
| 116 | pop(); |
| 117 | if (status == -1) { |
| 118 | dfn[u] = low[u] = ++cntd; |
| 119 | sta[++top] = u; |
| 120 | e = head[u]; |
| 121 | } else { |
| 122 | v = to[e]; |
| 123 | if (status == 0) { |
| 124 | low[u] = Math.min(low[u], low[v]); |
| 125 | } |
| 126 | if (status == 1 && belong[v] == 0) { |
| 127 | low[u] = Math.min(low[u], dfn[v]); |
| 128 | } |
| 129 | e = nxt[e]; |
| 130 | } |
| 131 | if (e != 0) { |
| 132 | v = to[e]; |
| 133 | if (dfn[v] == 0) { |
| 134 | push(u, 0, e); |
| 135 | push(v, -1, -1); |
| 136 | } else { |
| 137 | push(u, 1, e); |
| 138 | } |
| 139 | } else { |
| 140 | if (dfn[u] == low[u]) { |
| 141 | sccCnt++; |
| 142 | int pop; |
| 143 | do { |
| 144 | pop = sta[top--]; |
| 145 | belong[pop] = sccCnt; |
| 146 | } while (pop != u); |
| 147 | } |
| 148 | } |
| 149 | } |
| 150 | } |
| 151 | |
| 152 | public static void main(String[] args) throws Exception { |
| 153 | FastReader in = new FastReader(System.in); |