how to merge two sorted array in one sorted array in JavaScript without using sort()

Question

In this program merged two array and then sorted using temp.but this not correct method.because two array are sorted ,so method should be unique i.e. merging of two sorted i

Answer 1

I have been working on it for while now, and I have found a good solution. I didn't came up with this algorithm, but I implemented it properly in Javscript. I have tested it with massive number of array, and I have included comments so it's easier to understand. Unlike many other solutions, this one of the most efficient one, and I have included some tests. You run the code to verify that works. Time Complexity of a this solution is O(n)

function mergeTwoSortedArraay(rightArr, leftArr) {
 // I decided to call frist array "rightArr" and second array "leftArr"
  var mergedAr = [], sizeOfMergedArray = rightArr.length + leftArr.length; // so if rightArray has 3 elements and leftArr has 4, mergedArray will have 7.
   var r = 0, l =0; // r is counter of rightArr and l is for leftArr;
   for(var i =0; i< sizeOfMergedArray; ++i) {
       if(rightArr[r] >= leftArr[l] || r >= rightArr.length) { // r >= rightArr.length when r is equal to greater than length of array, if that happens we just copy the reaming 
        // items of leftArr to mergedArr

            mergedAr[i] = leftArr[l];
            l++;
       } else { 
           mergedAr[i] = rightArr[r];
           r++;
       }
   }
   return mergedAr;
}
// few tests
console.log(mergeTwoSortedArraay([ 0, 3, 4, 7, 8, 9 ],[ 0, 4, 5, 6, 9 ]));

console.log(mergeTwoSortedArraay([ 7, 13, 14, 51, 79 ],[ -356, 999 ]));
console.log(mergeTwoSortedArraay([ 7, 23, 64, 77 ],[ 18, 42, 45, 90 ]));