implementation of bitmap

#define shift 5
#define tail 0x1F
#define bitword 32
#define N 10000000
int a[1+N/bitword];

void Set(int i){
  a[i>>shift] |= 1<<(i&tail);
}

void Clr(int i){
  a[i>>shift] &= ~(1<<(i&tail));
}

int test(int i){
  return a[i>>shift] & 1<<(i&tail);
}
=============

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