Find repeated character present first in a string

<script>

// Javascript program to find the first
// character that is repeated
function findRepeatFirstN2(s)
{
    
    // This is O(N^2) method
    let p = -1, i, j;
    for(i = 0; i < s.length; i++)
    {
        for(j = i + 1; j < s.length; j++)
        {
            if (s[i] == s[j])
            {
                p = i;
                break;
            }
        }
        if (p != -1)
            break;
    }
    return p;
}

// Driver code
let str = "geeksforgeeks";
let pos = findRepeatFirstN2(str);

if (pos == -1)
    document.write("Not found");
else
    document.write(str[pos]);
    
// This code is contributed by suresh07   

</script>

<script>
    // Javascript Program to find the first character that is repeated
    
    function findRepeatFirst(s)
    {
        // this is optimized method
        let p = -1, i, k;
  
        // initialized counts of occurrences of
        // elements as zero
        let MAX_CHAR = 256;
        let hash = new Array(MAX_CHAR);
        hash.fill(0);
  
        // initialized positions
        let pos = new Array(MAX_CHAR);
        pos.fill(0);
  
        for (i = 0; i < s.length; i++)
        {
            k = s[i].charCodeAt();
            if (hash[k] == 0)
            {
                hash[k]++;
                pos[k] = i;
            }
            else if (hash[k] == 1)
                hash[k]++;
        }
  
        for (i = 0; i < MAX_CHAR; i++)
        {
            if (hash[i] == 2)
            {
                if (p == -1) // base case
                    p = pos[i];
                else if (p > pos[i])
                    p = pos[i];
            }
        }
  
        return p;
    }
    
    let str = "geeksforgeeks";
    let pos = findRepeatFirst(str);
    if (pos == -1)
      document.write("Not found");
    else
      document.write(str[pos]);

// This code is contributed by rameshtravel07.
</script>

// JavaScript implementation
// Function which repeats 
// first repeating character
function printrepeated(string) {
  
    // Calculating frequencies 
    // using an object to store character counts
    let freq = {};
    for (let i = 0; i < string.length; i++) {
        if (string[i] in freq) {
            freq[string[i]] += 1;
        } else {
            freq[string[i]] = 1;
        }
    }
    
    // Traverse the string
    for (let i = 0; i < string.length; i++) {
        if (freq[string[i]] > 1) {
            console.log(string[i]);
            break;
        }
    }
}

// Driver code
let string = "geeksforgeeks";

// passing string to printrepeated function
printrepeated(string);

// this code is contributed by princekumaras

<script>
// JavaScript code to find the first repeating character in a string
const INT_MAX = 2147483647

// Function to find left most repeating character.
function firstRep(s)
{
    map = new Map();
    let c = '#';
    let index=INT_MAX;
        
    // single traversal of string.
    for(let i = 0; i < s.length; i++)
    {
        let p = s[i];
            
        if(!map.has(p))map.set(p,i);
        else
        {
            if(map.get(p) < index)
            {
                index = map.get(p);
                c = p;
            }
        }         
    } 
    return c;
}

// Driver code

// Input string.
const s="abccdbd";
document.write(firstRep(s));
    
// This code is contributed by shinjanpatra
</script>