findTheTownJudge.js

findTheTownJudge.js

const findJudge = (N, trust) => {
    // keep track of how many likes the element gives
    let likesCountList = {}
    //keep track of how many likes the element receives
    let beingLikedCountList = {}
    
    //hash the key from 1 to N
    for(let i = 1; i <= N; i++){
        likesCountList[i] = 0
        beingLikedCountList[i] = 0
    }
    
    //loop through trust to hash value to hashes
    for(let ele of trust){
        likesCountList[ele[0]]++
        beingLikedCountList[ele[1]]++
    }
    
    //variable to store potential judge
    
    let judge = 0
    //if the element doesn't give out any likes
    //it is the potantial judge
    for(key in likesCountList){
        if(likesCountList[key] === 0) judge = key
    }
    
    //if the potential judge receives likes from everybody other than itself
    //it means it is the judge
    //otherwise judge doesn't exist
    
    if(beingLikedCountList[judge] === N - 1) return judge
    else return -1
    
    
   
};