Create 2348-number-of-zero-filled-subarrays.cpp

Author: Abe0770

cpp/2348-number-of-zero-filled-subarrays.cpp

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+/*
+    Given an integer array nums, return the number of subarrays filled with 0.
+    A subarray is a contiguous non-empty sequence of elements within an array.
+
+    Ex. Input: nums = [1,3,0,0,2,0,0,4]
+          Output: 6
+	  Explanation: 
+	  There are 4 occurrences of [0] as a subarray.
+	  There are 2 occurrences of [0,0] as a subarray.
+	  There is no occurrence of a subarray with a size more than 2 filled with 0. Therefore, we return 6.
+
+    Time  : O(N)
+    Space : O(1) 
+*/
+
+class Solution {
+public:
+    long long zeroFilledSubarray(vector<int>& nums) {
+        long long res = 0, count = 0;
+        for (int i = 0; i < nums.size(); i++) {
+            if (nums[i]) {
+                res += (count * (count + 1)) / 2;
+                count = 0;
+            } else 
+                ++count;
+        }
+        res += (count * (count + 1)) / 2;
+        return res;
+    }
+};