UVA 1326 B - Jurassic Remains——暴力

不用位运算会超时

#include <cstdio>
using namespace std;
int main() {
char str[30];
int n, a[30], cnt, ans;
while (~scanf("%d", &n)) {
for (int i = 0; i < n; i++) {
scanf("%s", str);
a[i] = 0;
for (int j = 0; str[j]; j++) a[i] ^= (1<<(str[j] - 'A'));
}
cnt = ans = 0;
for (int i = 1; i < (1<<n); i++) {
int t = 0, c = 0;
for (int j = 0; j < n; j++) if (i & (1<<j)) t ^= a[j], c++;
if (t == 0 && c > cnt) {
cnt = c, ans = i;
}
}
int flag = 0;
printf("%d\n", cnt);
for (int i = 0; i < n; i++) {
if (ans & (1<<i)) {
if (flag++) printf(" ");
printf("%d", i + 1);
}
}
printf("\n");
}
}