init

7A.py

@@ -0,0 +1,51 @@
+import sys
+
+data = sys.stdin.read().split()
+n, m = int(data[0]), int(data[1])
+parents = [0] * n
+idx = 2
+for i in range(1, n):
+    parents[i] = int(data[idx])
+    idx += 1
+a1, a2 = int(data[idx]), int(data[idx+1])
+x, y, z = int(data[idx+2]), int(data[idx+3]), int(data[idx+4])
+adj = [[] for _ in range(n)]
+for i in range(1, n):
+    adj[parents[i]].append(i)
+depth = [0] * n
+q = [0]
+for u in q:
+    for v in adj[u]:
+        depth[v] = depth[u] + 1
+        q.append(v)
+up = [[0] * 18 for _ in range(n)]
+for i in range(1, n):
+    up[i][0] = parents[i]
+for k in range(1, 18):
+    for i in range(n):
+        up[i][k] = up[up[i][k-1]][k-1]
+a = [0] * (2 * m + 1)
+a[1], a[2] = a1, a2
+for i in range(3, 2 * m + 1):
+    a[i] = (x * a[i-2] + y * a[i-1] + z) % n
+ans = 0
+v = 0
+for i in range(1, m + 1):
+    u = (a[2*i-1] + v) % n
+    vq = a[2*i]
+    if depth[u] < depth[vq]:
+        u, vq = vq, u
+    diff = depth[u] - depth[vq]
+    for k in range(18):
+        if (diff >> k) & 1:
+            u = up[u][k]
+    if u == vq:
+        v = u
+    else:
+        for k in range(17, -1, -1):
+            if up[u][k] != up[vq][k]:
+                u = up[u][k]
+                vq = up[vq][k]
+        v = up[u][0]
+    ans += v
+print(ans)