Update 907-sum-of-subarray-minimums.js

Author: everthis

907-sum-of-subarray-minimums.js

@@ -2,33 +2,36 @@
  * @param {number[]} arr
  * @return {number}
  */
-const sumSubarrayMins = function(arr) {
-  const n = arr.length, s1 = [], s2 = [], left = Array(n), right = Array(n)
-  for(let i = 0; i < n; i++) {
+const sumSubarrayMins = function (arr) {
+  const n = arr.length,
+    s1 = [],
+    s2 = [],
+    left = Array(n),
+    right = Array(n)
+  for (let i = 0; i < n; i++) {
     let cnt = 1
-    while(s1.length && s1[s1.length - 1][0] > arr[i]) {
+    while (s1.length && s1[s1.length - 1][0] > arr[i]) {
       cnt += s1.pop()[1]
     }
     left[i] = cnt
     s1.push([arr[i], cnt])
   }
-  
-  for(let i = n - 1; i >= 0; i--) {
+
+  for (let i = n - 1; i >= 0; i--) {
     let cnt = 1
-    // use ">=" to deal with duplicate elements
-    while(s2.length && s2[s2.length - 1][0] >= arr[i]) {
+    while (s2.length && s2[s2.length - 1][0] >= arr[i]) {
       cnt += s2.pop()[1]
     }
     right[i] = cnt
     s2.push([arr[i], cnt])
   }
   let res = 0
   const mod = 1e9 + 7
-  for(let i = 0; i < n; i++) {
+  for (let i = 0; i < n; i++) {
     // left[i] number of starting positions
     // right[i] number of ending positions
     res = (res + arr[i] * left[i] * right[i]) % mod
   }
-  
+
   return res
-};
+}