Two Sum

two-sum.js

/**
 * @param {number[]} nums
 * @param {number} target
 * @return {number[]}
 */
var twoSum = function(nums, target) {
    
    //hash table
    var hash = {};

    for(let currentNumIndex=0; currentNumIndex <=nums.length; currentNumIndex++){
      
        //current number
        var currentNumber = nums[currentNumIndex];
        console.log({currentNumber})
      
        //difference in the target and current number
        var requiredNumber = target - currentNumber;
        console.log({requiredNumber})
      
        // find the difference number from hashTable
        const indexOfRequiredNumber = hash[requiredNumber];
        console.log({indexOfRequiredNumber})
        
        // if number found in hash, return index 
        // it will return undefined if not found
        if(indexOfRequiredNumber != undefined) {
            return [indexOfRequiredNumber, currentNumIndex]
        } else {
           // if not number found, we add the number into the hashTable
           hash[currentNumber] = currentNumIndex;
        }
        console.log({hash})
    }
    
};