Find repeated elements in a having count

- (NSArray *)mostCharInString:(NSString *)string count:(int *)count{
    NSMutableDictionary *dict = [NSMutableDictionary dictionary];
    int len = string.length;
    NSRange theRange = {0, 1};
    for (NSInteger i = 0; i < len; i++) {
        theRange.location = i;
        NSString *charStr = [string substringWithRange:theRange];
        int preCount = 0;
        if ([dict objectForKey:charStr]) {
            preCount = [[dict objectForKey:charStr] unsignedIntegerValue];
        }
        [dict setObject:@(preCount+1) forKey:charStr];
    }
    NSArray *sortValues = [[dict allValues] sortedArrayUsingSelector:@selector(compare:)];
    *count = [[sortValues lastObject] unsignedIntegerValue];
    return  [dict allKeysForObject:@(*count)];
}

int mostRepeatCount = 0;
NSArray *mostChars = nil;
mostChars = [self mostCharInString:@"aaabbbcccc" count:&mostRepeatCount];
NSLog(@"count:%d char:%@", mostRepeatCount, mostChars);

count:4 char:(
    c
)

mostChars = [self mostCharInString:@"aaabbbccccdddd" count:&mostRepeatCount];

count:4 char:(
    d,
    c
)

table(z[z %in% x])
# 
# 1 2 4 
# 2 1 1 

sum(table(z[z %in% x]))
# [1] 4

for i in range(len(alist)-1):
    if(alist[i] == alist[i+1]):
        counter+=2    # since you count both elements

alist=[1,2,2,3,3,5,6] # 4
alist=[4,5,6,6,8,8,8,8] # 8