Create 0930-binary-subarrays-with-sum.kt

Author: a93a

kotlin/0930-binary-subarrays-with-sum.kt

@@ -0,0 +1,24 @@
+class Solution {
+    fun numSubarraysWithSum(nums: IntArray, goal: Int): Int {
+
+        fun helper(x: Int): Int {
+            if (x < 0) return 0
+
+            var res = 0
+            var l = 0
+            var cur = 0
+            for (r in 0 until nums.size) {
+                cur += nums[r]
+
+                while (cur > x)
+                    cur -= nums[l++]
+
+                res += (r - l + 1)
+            }
+
+            return res
+        }
+
+        return helper(goal) - helper(goal - 1)
+    }
+}