AI solution for JavaScript Coding Question on BFE.dev
81. merge sorted arrays

One possible solution with a time complexity of O(n log n) is:

function merge(arrays) {  let result = [];  // Merge each pair of adjacent arrays  while (arrays.length > 1) {    let merged = [];    let a = arrays.shift();    let b = arrays.shift();    let i = 0;    let j = 0;    while (i < a.length && j < b.length) {      if (a[i] <= b[j]) {        merged.push(a[i]);        i++;      } else {        merged.push(b[j]);        j++;      }    }    while (i < a.length) {      merged.push(a[i]);      i++;    }    while (j < b.length) {      merged.push(b[j]);      j++;    }    arrays.push(merged);  }  // Concatenate the remaining arrays  result = arrays[0] || [];  for (let i = 1; i < arrays.length; i++) {    result = result.concat(arrays[i]);  }  return result;}

The solution uses a loop to repeatedly merge pairs of adjacent arrays into a single larger array until there is only one array remaining. This takes O(log n) iterations, where n is the number of input arrays.

Inside each iteration, we perform a merge of two arrays, which takes O(n) time, where n is the total number of elements in the two arrays.

Finally, we concatenate the remaining arrays, which takes O(n) time, where n is the total number of remaining elements.

Overall, the time complexity of this solution is O(n log n).