init

2A.py

@@ -0,0 +1,67 @@
+import sys
+
+
+data = sys.stdin.read().split()
+ptr = 0
+
+
+while ptr < len(data):
+    n = int(data[ptr])
+    ptr += 1
+    m = int(data[ptr])
+    ptr += 1
+    N = 2 * n
+    g = [[] for _ in range(N)]
+    gr = [[] for _ in range(N)]
+    for _ in range(m):
+        i1 = int(data[ptr]); ptr += 1
+        e1 = int(data[ptr]); ptr += 1
+        i2 = int(data[ptr]); ptr += 1
+        e2 = int(data[ptr]); ptr += 1
+        u_neg = 2 * i1 + (1 - e1)
+        v_neg = 2 * i2 + (1 - e2)
+        u_pos = 2 * i1 + e1
+        v_pos = 2 * i2 + e2
+        g[u_neg].append(v_pos)
+        gr[v_pos].append(u_neg)
+        g[v_neg].append(u_pos)
+        gr[u_pos].append(v_neg)
+    visited = [False] * N
+    order = []
+    for i in range(N):
+        if not visited[i]:
+            stack = [(i, 0)]
+            visited[i] = True
+            while stack:
+                cur, edge_idx = stack[-1]
+                if edge_idx < len(g[cur]):
+                    next_node = g[cur][edge_idx]
+                    stack[-1] = (cur, edge_idx + 1)
+                    if not visited[next_node]:
+                        visited[next_node] = True
+                        stack.append((next_node, 0))
+                else:
+                    order.append(cur)
+                    stack.pop()
+    comp = [-1] * N
+    c_id = 0
+    for i in range(N - 1, -1, -1):
+        start_node = order[i]
+        if comp[start_node] == -1:
+            c_id += 1
+            stack = [start_node]
+            comp[start_node] = c_id
+            while stack:
+                cur = stack.pop()
+                for neighbor in gr[cur]:
+                    if comp[neighbor] == -1:
+                        comp[neighbor] = c_id
+                        stack.append(neighbor)
+
+    res = []
+    for i in range(n):
+        if comp[2 * i + 1] > comp[2 * i]:
+            res.append("1")
+        else:
+            res.append("0")
+    print("".join(res))