Find frequency of consecutive digits N times-CodePudding

Given a string of digits and a number n String = 500055 n = 2

then output -> 510352 explanation: here I'm counting the frequency of consecutive digits and storing them. in 500055,

5 is occurring consecutively 1 time --- (51)

0 is occurring consecutively 3 times --- (5103)

5 is occurring consecutively 2 times --- (510352)

example 2:

String = 500055

n = 3

500055 -> 510352 -> 511101315121

(basically applying the same function again on n=2)

example 3:

String = 500055

n = 4

500055 -> 510352 -> 511101315121 -> 51130111311151112111

example 4:

String = 500055

n = 1

output 500055

Is there any way to solve this in one pass?

like: String = 500055 n = 4

500055 -> 51130111311151112111

CodePudding user response：

Sounds like you are wondering if there is some predictive formula to use. Since the actual digits change based on previous constructions, I would think it unlikely (at least not straight mathematically - but I could be wrong). In any event, this was certainly faster to derive (for me) and you don't need to explicitly count anything. Just use a regex and the String.length method.

String start = "500055";
for (int n = 0; n < 4; n  ) {
    String s = consecutiveCount(start, n);
    System.out.printf("n = %d : %s -> %s%n", n, start, s);
}

prints

n = 0 : 500055 -> 500055
n = 1 : 500055 -> 510352
n = 2 : 500055 -> 511101315121
n = 3 : 500055 -> 51130111311151112111

The method.

(\\d)\\1* - capture a digit followed by 0 or more of the same digit (using a back reference to group1.
concatentate the character in group1 followed by the length of the entire match (group0).
repeat until find() returns false
then create a new matcher for the new string.
set the string to empty.
and continue the next iteration.

final static String REGEX = "(\\d)\\1*";
final static Pattern PATTERN = Pattern.compile(REGEX);

public static String consecutiveCount(String str, int iterations) {
    while (iterations-- > 0) {
        Matcher m = PATTERN.matcher(str);
        str = "";
        while (m.find()) {
            str  = m.group(1)   ""
                      m.group(0).length();
        }   
    }
    return str;
}

Note: As mentioned in my comment, you may need to alter either your or my interpretation of n

CodePudding user response：

You can use streams for that job:

public static String frequency(String digits, int n) {
    return n < 2 ? digits : frequency(frequency(digits), n - 1);
}

public static String frequency(String digits) {
    return IntStream.range(0, digits.length())
            .filter(i -> i == digits.length() - 1 || digits.charAt(i) != digits.charAt(i   1))
            .mapToObj(i -> String.valueOf(digits.charAt(i)) 
                      (i == 0 ? i   1 : IntStream.range(0, i)
                            .filter(j -> digits.substring(j, i).chars()
                                    .allMatch(c -> c == digits.charAt(i)))
                            .count()   1))
            .collect(Collectors.joining());
}

Then:

String digits = "500055";
    
System.out.println("n = 1: "   frequency(digits, 1));
System.out.println("n = 2: "   frequency(digits, 2));
System.out.println("n = 3: "   frequency(digits, 3));
System.out.println("n = 4: "   frequency(digits, 4));

Output:

n = 1: 500055
n = 2: 510352
n = 3: 511101315121
n = 4: 51130111311151112111

CodePudding user response：

you can use this code javascript countdown 10 seconds:

var timeleft = 10;
var downloadTimer = setInterval(function(){
  if(timeleft <= 0){
    clearInterval(downloadTimer);
  }
  document.getElementById("progressBar").value = 10 - timeleft;
  timeleft -= 1;
}, 1000);
<progress value="0" max="10" id="progressBar"></progress>

countdown in javascript :

<!DOCTYPE html>
<html lang="en">
   <head>
      <meta charset="UTF-8" />
      <title>Countdown timer using HTML and JavaScript</title>
   </head>
   <body>
      Registration closes in <span id="timer">05:00<span> minutes!

      <!-- custom js -->
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            var sec = 60;
            setInterval(function () {
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                  minute   " : "   sec;
               sec--;
               if (sec == 00) {
                  minute--;
                  sec = 60;
                  if (minute == 0) {
                     minute = 5;
                  }
               }
            }, 1000);
         };
      </script>
   </body>
</html>

countdown in js:

<body>
    <div>Registration closes in <span id="time">05:00</span> minutes!</div>
</body>