gistfile1.txt

```
- (NSUInteger *)binaryGap(NSInteger N) {
    NSMutableString *str = [NSMutableString stringWithFormat:@""];
   
    for (NSInteger NCopy = N; NCopy > 0; NCopy >>= 1) {
        [str insertString:((NCopy & 1) ? @"1": @"0") atIndex:0];
    }
   
    unichar buffer[str.length];
    [str getCharacters:buffer range:NSMakeRange(0, str.length)];
   
    NSInteger count = -1;
    NSInteger maxCount = 0;
    for (NSUInteger i = 0; i < str.length; i++) {
        char current = buffer[i];
        if (current == '0' && count >= 0) {
            count ++;
        } else {
            maxCount = MAX(maxCount, count);
            count = 0;
        }
    }
   
    return maxCount;
}
```