Update 1685-sum-of-absolute-differences-in-a-sorted-array.js

Author: everthis

1685-sum-of-absolute-differences-in-a-sorted-array.js

@@ -4,14 +4,14 @@
  */
 const getSumAbsoluteDifferences = function(nums) {
   const res = [], n = nums.length
-  let first = 0
-  for(let i = 1; i < n; i++) {
-    first += nums[i] - nums[0]
+  let sum = 0
+  for(let first = nums[0], i = 1; i < n; i++) {
+    sum += nums[i] - first
   }
-  res[0] = first
+  res[0] = sum
   for(let i = 1; i < n; i++) {
-    res[i] = res[i - 1] + (nums[i] - nums[i - 1]) * i - (nums[i] - nums[i - 1]) * (n - i)
+    res[i] = res[i - 1] - (nums[i] - nums[i - 1]) * (n - i - 1) + (nums[i] - nums[i - 1]) * (i - 1)
   }
-  
+
   return res
 };