Happy Matt Friends

浏览数：25 / 时间：2015年06月11日

Happy Matt Friends

Time Limit: 6000/6000 MS (Java/Others) Memory Limit: 510000/510000 K (Java/Others)
Total Submission(s): 0 Accepted Submission(s): 0

Problem Description

Matt has N friends. They are playing a game together.

Each of Matt’s friends has a magic number. In the game, Matt selects some (could be zero) of his friends. If the xor (exclusive-or) sum of the selected friends’magic numbers is no less than M , Matt wins.

Matt wants to know the number of ways to win.

Input

The first line contains only one integer T , which indicates the number of test cases.

For each test case, the first line contains two integers N, M (1 ≤ N ≤ 40, 0 ≤ M ≤ 10⁶).

In the second line, there are N integers ki (0 ≤ k_i ≤ 10⁶), indicating the i-th friend’s magic number.

Output

For each test case, output a single line “Case #x: y”, where x is the case number (starting from 1) and y indicates the number of ways where Matt can win.

Sample Input

3 2

1 2 3

3 3

1 2 3

Sample Output

Case #1: 4

Case #2: 2

Hint

In the ?rst sample, Matt can win by selecting: friend with number 1 and friend with number 2. The xor sum is 3. friend with number 1 and friend with number 3. The xor sum is 2. friend with number 2. The xor sum is 2. friend with number 3. The xor sum is 3. Hence, the answer is 4.

解题：dp计数

dp弱到渣啊！在码代码的猿猿巨巨指导下才搞定！

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 #include <cmath>
 5 #include <algorithm>
 6 #include <climits>
 7 #include <vector>
 8 #include <queue>
 9 #include <cstdlib>
10 #include <string>
11 #include <set>
12 #include <map>
13 #include <stack>
14 #define LL long long
15 #define INF 0x3f3f3f3f
16 #define pii pair<int,int>
17 using namespace std;
18 const int maxn = 1<<21;
19 int dp[2][maxn],d[41],n,m;
20 int main() {
21     int T,cs=1;
22     scanf("%d",&T);
23     while(T--) {
24         scanf("%d %d",&n,&m);
25         memset(dp,0,sizeof(dp));
26         for(int i = 0; i < n; ++i)
27             scanf("%d",d+i);
28         LL ans = 0;
29         dp[0][0] = 1;
30         int cur = 0;
31         for(int i = 0; i < n; ++i) {
32             memset(dp[cur^1],0,sizeof(dp[cur^1]));
33             for(int j = 0; j < maxn; ++j) {
34                 int tmp = j^d[i];
35                 dp[cur^1][tmp] += dp[cur][j];
36                 dp[cur^1][j] += dp[cur][j];
37             }
38             cur ^= 1;
39         }
40         for(int i = m; i < maxn; ++i)
41             if(dp[cur][i]) ans += dp[cur][i];
42         printf("Case #%d: %I64d\n",cs++,ans);
43     }
44     return 0;
45 }