combi tpa

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <assert.h>
#define NMAX 64

void mkAndPrintComb(int n, int k, const int arr[]) {
  assert(n <= 64 && k <= n);
  int cnt = 0;
  for (uint64_t state = 0; state < (1 << n); state++) {
    if (__builtin_popcount(state) != k) {
      continue;
    }
    printf("#%d: ", ++cnt);
    for (int i = 0; i < 64; i++) {
      if (1 & (state >> i)) {
        printf("%d ", arr[i]);
      }
    }
    putchar('\n');
  }
}

int main(void) {
  int n, k;
  scanf("%d%d", &n, &k);
  static int arr[NMAX];
  for (int i = 0; i < n; i++) {
    scanf("%d", arr + i);
  }
  mkAndPrintComb(n, k, arr);
  return 0;
}