50098. Disjoint Clubs
難度：4.2/5
將19行的i < n剪成i <= (k - cnt)可以從772 ms加速到254 ms。 記得只要跟uint64_t做operation，另一個operand也要typecast成uint64_t。
Second Try: 3/5 Used Time: 16:12 But my runtime is a lot worse...1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
int n, k;
uint64_t club[101] = {(uint64_t)0};
int dfs(int vis[], uint64_t in_members, int cnt, int now_c){
if(cnt == k){
for(int i = 0; i < n; i++){
if(vis[i]) printf("%d\n", i);
}
return 1;
}
else if(now_c == n){
return 0;
}
else{
for(int i = now_c; i <= n - (k - cnt); i++){
if((in_members & club[i]) != (uint64_t)0) continue;
vis[i] = 1;
int rtv = dfs(vis, in_members | club[i], cnt + 1, i + 1);
if(rtv) return 1;
vis[i] = 0;
}
return 0;
}
}
void print_bin(uint64_t n){
for(int i = 63; i >= 0; i--){
printf("%d", (n >> i) & (uint64_t)1);
}
printf("\n");
}
int main(){
scanf("%d %d", &n, &k);
for(int i = 0; i < n; i++){
int m; scanf("%d", &m);
for(int j = 0; j < m; j++){
int ppl; scanf("%d", &ppl);
club[i] |= ((uint64_t)1 << ppl);
}
}
int vis[101] = {0};
dfs(vis, (uint64_t)0, 0, 0);
}