桶排序-OC

    NSArray * b = @[@,@,@,@,@];
    NSMutableArray *a = @[].mutableCopy;
    for (int i=; i<; i++) {
        a[i] = @;
    }
    for (NSNumber *num in b) {
        int index = [num intValue];
        if(a[index]){
            a[index] = @([a[index] intValue] + );
        } else {
            a[index] = @;
        }
    }
    for (int i = ; i<a.count; i++) {
        if([a[i] intValue]>){
            NSLog(@"%d",i);
        }
    }