| 100 | |
| 101 | // 迭代版 |
| 102 | public static void tarjan2(int node, int pree) { |
| 103 | stacksize = 0; |
| 104 | push(node, pree, -1, -1); |
| 105 | int v; |
| 106 | while (stacksize > 0) { |
| 107 | pop(); |
| 108 | if (status == -1) { |
| 109 | dfn[u] = low[u] = ++cntd; |
| 110 | sta[++top] = u; |
| 111 | e = head[u]; |
| 112 | } else { |
| 113 | v = to[e]; |
| 114 | if (status == 0) { |
| 115 | low[u] = Math.min(low[u], low[v]); |
| 116 | } else { |
| 117 | low[u] = Math.min(low[u], dfn[v]); |
| 118 | } |
| 119 | e = nxt[e]; |
| 120 | } |
| 121 | if ((e ^ 1) == preEdge) { |
| 122 | e = nxt[e]; |
| 123 | } |
| 124 | if (e != 0) { |
| 125 | v = to[e]; |
| 126 | if (dfn[v] == 0) { |
| 127 | push(u, preEdge, 0, e); |
| 128 | push(v, e, -1, -1); |
| 129 | } else { |
| 130 | push(u, preEdge, 1, e); |
| 131 | } |
| 132 | } else { |
| 133 | if (dfn[u] == low[u]) { |
| 134 | ebccCnt++; |
| 135 | ebccSiz[ebccCnt] = 0; |
| 136 | ebccl[ebccCnt] = idx + 1; |
| 137 | int pop; |
| 138 | do { |
| 139 | pop = sta[top--]; |
| 140 | ebccSiz[ebccCnt]++; |
| 141 | ebccArr[++idx] = pop; |
| 142 | } while (pop != u); |
| 143 | ebccr[ebccCnt] = idx; |
| 144 | } |
| 145 | } |
| 146 | } |
| 147 | } |
| 148 | |
| 149 | public static void main(String[] args) throws Exception { |
| 150 | FastReader in = new FastReader(System.in); |