add solution to 2348 number of zero filled subarray

Author: Sam Luo

javascript/2348-number-of-zero-filled-subarrays.js

@@ -0,0 +1,21 @@
+/*
+ * Time O(N) | Space O(1)
+ * https://leetcode.com/problems/number-of-zero-filled-subarrays
+ */
+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+var zeroFilledSubarray = function(nums) {
+    let total, count;
+    total = count = 0;
+    for(let element of nums){
+        if(element == 0){
+            count ++;
+            total += count;
+        }else{
+            count = 0;
+        }
+    };
+    return total;
+};