第十五周 12.6-12.12

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 using namespace std;
 5 const int maxn = 500000 + 10;
 6 typedef long long LL;
 7 int cnt, headlist[maxn];
 8 int a[maxn][11], b[maxn][11];
 9 int ans[maxn];
10 LL N, K, A, B;
11 
12 struct node
13 {
14     int to,pre;
15 } edge[maxn * 2];
16 
17 void add(int from,int to)
18 {
19     cnt++;
20     edge[cnt].pre = headlist[from];
21     edge[cnt].to = to;
22     headlist[from] = cnt;
23 }
24 
25 void dfs1(int pos, int fa)
26 {
27     a[pos][0] = 1;
28     for(int i = headlist[pos]; i; i = edge[i].pre)
29     {
30         int to = edge[i].to;
31         if(to == fa) continue;
32         dfs1(to, pos);
33         a[pos][1]++;
34         for(int j = 1; j < K; j++) a[pos][j+1] += a[to][j];
35     }
36     return;
37 }
38 
39 void dfs2(int pos, int fa)
40 {
41     if(fa != 0)
42     {
43         b[pos][1]++;
44         for(int i = 1; i < K; i++) b[pos][i+1] += b[fa][i] - a[pos][i-1];
45     }
46     for(int i = 0; i <= K; i++) b[pos][i] += a[pos][i] ,ans[pos] += b[pos][i];
47     for(int i = headlist[pos]; i; i = edge[i].pre)
48     {
49         int to = edge[i].to;
50         if(to == fa) continue;
51         dfs2(to, pos);
52     }
53     return;
54 }
55 
56 int main(void)
57 {
58     int T;
59     scanf("%d", &T);
60     while(T--)
61     {
62         scanf("%I64d %I64d %I64d %I64d", &N, &K, &A, &B);
63         cnt = 0;
64         memset(headlist, 0, sizeof(headlist));
65         memset(a, 0, sizeof(a));
66         memset(b, 0, sizeof(b));
67         memset(ans, 0, sizeof(ans));
68         for(LL i = 2; i <= N; i++)
69         {
70             LL b = (A * i + B) % (i - 1) + 1;
71             add(i, b);
72             add(b, i);
73         }
74         dfs1(1,0);
75         dfs2(1,0);
76         int ret = 0;
77         for(int i = 1; i <= N; i++) ret ^= ans[i];
78         printf("%d\n", ret);
79     }
80     return 0;
81 }