20200723T1 【NOIP2015模拟10.28A组】同余

Description

Input

Output

Sample Input

2
1 1 5 100
3
2 0 7 7
2 2

Sample Output

16
0

Data Constraint

 solution

日常先打指数暴力dfs水30分

 1 void dfs(int x, int y)
 2 {
 3     if(x == n + 1 && y == 1)
 4     {
 5         int sum = 0;
 6         for(R int i = 1; i <= n; i++)
 7         {
 8             int kkk = 1;
 9             for(R int j = 1; j <= a[i]; j++)
10             {
11                 kkk *= b[i][j];
12             }
13             sum = (sum + kkk) % p;
14         }
15         if(sum == c) ans++, ans %= m ;
16         return;
17     }
18     if(y == a[x])
19     {
20         for(R int i = 0; i < p; i++)
21         {
22             b[x][y] = i;
23             dfs(x + 1, 1);
24             b[x][y] = 0;
25         }
26         return;
27     }
28     for(R int i = 0; i < p; i++)
29     {
30         b[x][y] = i;
31         dfs(x, y + 1);
32         b[x][y] = 0;
33     }
34     return;
35 }
36 signed main()
37 {
38     freopen("congruence.in","r",stdin);
39     freopen("congruence.out","w",stdout);
40     read(t);
41     while(t--)
42     {
43         read(n); read(c); read(p); read(m );
44         ans = 0;
45         for(R int i = 1; i <= n; i++) read(a[i]);
46         dfs(1, 1);
47         writeln(ans);
48     }
49     return 0;
50 }

先挖坑，A了再来

code