CODEWITHSUNDEEP
javascriptstring
user3596335
user3596335

Reputation:

Detect same occurrence in string

Let us assume I got two strings. In my case the strings are "stringA" and "stringB":

Example 1: 

let stringA = "1ABC DEFGHI";

let stringB = "XYZABC DEFGHI";

Even if the two strings are not exactly the same, they still contain a large amount of letter sequences, which are identical in both. In the case above it is the string "ABC DEFGHI" that occurs in both of them.

Example 2: And heres another example:

let stringA = "0142 41193566"

let stringB = "+49 142 41193566"

In this case the result should be 142 41193566 because this string occurs in both of them.

I would describe the operation as a kind of mask operation, but I have not progressed so far in implementing it. Unfortunately, this code snippet is everything I can offer so far.

let stringA = "0142 41193566"
let stringB = "+49 142 41193566"


let stringC = "....ThISisATest"
let stringD = "+Th.ISisATest33"


let detectBiggestOccurrence = function(stringA, stringB) {
  let result = []
  for (let c in stringA) {
    if (stringB.includes(stringA[c])) {
      let index = stringB.indexOf(stringA[c])
      result+=stringB[index]
    }
  }; return result
}


let resultWorking = detectBiggestOccurrence(stringA, stringB)
console.log("working:", resultWorking)


let resultNotWorking = detectBiggestOccurrence(stringC, stringD)
console.log("not working:", resultNotWorking)

Issue: The code above is working for the first call (detectBiggestOccurrence(stringA, stringB)) but it does not work for the second one (detectBiggestOccurrence(stringC, stringD)).

Upvotes: 3

Views: 124

Answers (2)

Carsten Massmann
Carsten Massmann

Reputation: 28196

Here is a modified version of Pierre Capo's answer. It will return a correct result, even if a "problematic" string should be tested (see my comment under Pierre's answer).

function maxmatch(a,b){
      var i=0,res='',pat=a[i];
      while (i<a.length) {
        if (b.includes(pat)) {
          if (pat.length>res.length) res=pat;
          pat+=a[++i];
        }
        else {
          if (pat.length>1) pat=pat.slice(1);
          else pat=a[++i];
        }
      }
     return res;
    }


    let testStrings=[["1ABC DEFGHI","XYZABC DEFGHI"],
    ["1ABC DEFGHI","XYZBC DEFGHI ABC"],
    ["0142 41193566","+49 142 41193566"],
    ["....ThISisATest","+Th.ISisATest33"]];
    
    testStrings.forEach(t=>console.log(maxmatch(...t)))

When applied to the test strings (please notice: I added a modified version of the first test string) they will all return the correct answer:

ABC DEFGHI
BC DEFGHI
142 41193566
ISisATest

Upvotes: 0

Pierre Capo
Pierre Capo

Reputation: 1053

The approach that I've used to solve your problem :

  1. Create an empty mask
  2. Populate that empty mask by one letter in first string and check if the mask is present in the second string.
  3. Compare mask length with last response length. If mask is bigger, mask becomes the response

function detectBiggestOccurrence(stringA, stringB){
    var mask ="";
    var response ="";
    stringA.split('').forEach( el => {
	    mask +=el;
        if(stringB.includes(mask)){
  	        if(mask.length > response.length){ response = mask; }
        }
        else { 
            mask =el;
        }
    })
    return response;
}

let stringA = "1ABC DEFGHI";
let stringB = "XYZABC DEFGHI";
console.log(detectBiggestOccurrence(stringA, stringB));

let stringC = "0142 41193566";
let stringD = "+49 142 41193566";
console.log(detectBiggestOccurrence(stringC, stringD));

let stringE = "....ThISisATest"
let stringF = "+Th.ISisATest33"
console.log(detectBiggestOccurrence(stringE, stringF));

Upvotes: 2

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