将 aaabbcccaabcd 输出为3a2b3c2a1b1c1d char_count(@"aaabbcccaabcd");

//aaabbcccaabcd -> 3a2b3c2a1b1c1dNSString* char_count(NSString* str) {    if (!str.length) return @"Please input a str";    NSMutableDictionary *charRepeatCountDICTM = [NSMutableDictionary new];    char lastChar = [str characterAtIndex:0];    NSString *lastStr = [NSString stringWithFormat:@"%c", lastChar];    charRepeatCountDICTM[[NSString stringWithFormat:@"%c", lastChar]] = @1;    NSMutableString *readableStrM = [NSMutableString new];    for (NSInteger i = 1; i < str.length; i++) {        char curChar = [str characterAtIndex:i];        NSString *curStr = [NSString stringWithFormat:@"%c", curChar];        NSNumber *repeatValue = charRepeatCountDICTM[curStr];        if (!repeatValue) {            charRepeatCountDICTM[curStr] = repeatValue = @1;        }        if ((int)lastChar == (int)curChar) {            NSInteger value = repeatValue.integerValue;            charRepeatCountDICTM[curStr] = @(++value);        } else {            NSInteger lastRepeatCount = [charRepeatCountDICTM[lastStr] integerValue];            [readableStrM appendString:[NSString stringWithFormat:@"%ld%c", lastRepeatCount, lastChar]];            [charRepeatCountDICTM removeObjectForKey:lastStr];        }        lastChar = curChar;        lastStr = [NSString stringWithFormat:@"%c", lastChar];    }    if (charRepeatCountDICTM.allKeys) {        [readableStrM appendString:[NSString stringWithFormat:@"%ld%c", [charRepeatCountDICTM[lastStr] integerValue], lastChar]];    }    return readableStrM.copy;}复制代码