1524

Author: theforestvn88

1501-1600/1524_number_of_sub_arrays_with_odd_sum.rb

@@ -0,0 +1,22 @@
+# @param {Integer[]} arr
+# @return {Integer}
+def num_of_subarrays(arr)
+    mod = 1000000007
+    count = 0
+    odd_count = 0
+    even_count = 0
+    sum = 0
+    arr.each { |x|
+        sum += x
+        if sum.odd?
+            odd_count += 1
+            count += even_count + 1
+        else
+            even_count += 1
+            count += odd_count
+        end
+        count %= mod
+    }
+
+    count % mod
+end