```
bool containsDuplicate(vector<int>& nums) {
if(nums.size()<2)return false;
int check[223323232>>8];
memset(check,0,sizeof(check));
for(n:nums){
if((check[n/32]&1<<(n%32))>0)return true;
check[n/32]|=1<<(n%32);
}
return false;
}
```