CODEWITHSUNDEEP
javascript
Drop
Drop

Reputation: 1582

How find the length of the longest substring?

Need find the length of the longest substring that consists of the same letter. For example, line "aaabbcaaaa" contains four substrings with the same letters "aaa", "bb","c" and "aaaa".

i found two way to do that, but all not so good;

At first way i don't make check previos similar letters here sdsffffse; Because i check only current element and second element if(line[i] === line[i+1]).

At second way i fail when i try to check how many aa i found in that string abababaab but in object i add all a letters and length = 5;

function longRepeat(line) {
    let count = {};
  	let letter = [];
  for (let i=0; i<line.length; i++) {
  	count[line[i]] = i;
    if(line[i] === line[i+1]){
          letter.push([line[i], line[i+1]])
    }
  }

  
/*
second way
for (let x of line) {
    count[x] = ~~count[x] + 1;
 } */
  
  return letter;
}

console.log(longRepeat('sdsffffse')); f = 4
console.log(longRepeat('ddvvrwwwrggg')); = 3
console.log(longRepeat('abababaab')); // last two a = 2

Upvotes: 0

Views: 539

Answers (3)

Clare_Cheng
Clare_Cheng

Reputation: 1

#python
def long_repeat(line):
    line = line.lower()
    max = 1
    if len(line) == 0:
        return 0
    for i in range(0, len(line) - 1):
        count = 1
        while line[i] == line[i + 1]:
            count += 1
            if max < count:
                max = count
            if i < len(line) - 2:
                i += 1
            else:
                break
    return max

Upvotes: 0

user7148391
user7148391

Reputation:

If you don't mind using regular expressions.

function func(line) {
  let reg = /(\w)\1+/g;
  let longest = line.match(reg).sort((a, b) => {
    a.length - b.length
  }).pop();
  console.log(line + ' : ' + longest);
}

func('ddvvrwwwrggg');
func('sdsffffse');
func('abababaab');
func('aaabbcaaaa');
func('aaaasdfbbbbyyyweryyyuurweuuuuuu');

/(\w)\1+/g will match a sequence of the same character, using the match() method we get all the sequences, sort them by length, and get the last item in the array, i didn't know what to do in case of equal length, so i'll leave that you, i'm merely presenting an idea, and it's for you to improve it :)

Upvotes: 1

Georgy
Georgy

Reputation: 2462

Possible solution:

function longestSubstr(str) {
  if (!str) return 0
  let maxL = 1
  let curL = 1
  for (let i = 0; i < str.length - 1; i++) {
    let cur = str[i]
    let next = str[i + 1]
    if (cur === next) {
      curL++
    } else {
      if (maxL < curL) maxL = curL
      curL = 1
    }
  }
  if (maxL < curL) maxL = curL
  return maxL
}

console.log(longestSubstr("abababaab")) // 2

Upvotes: 1

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