Create 3209-number-of-subarrays-with-and-value-of-k.js

Author: everthis

3209-number-of-subarrays-with-and-value-of-k.js

@@ -0,0 +1,46 @@
+/**
+ * @param {number[]} nums
+ * @param {number} k
+ * @return {number}
+ */
+var countSubarrays = function (nums, k) {
+  return atLeastK(nums, k) - atLeastK(nums, k + 1)
+}
+
+function atLeastK(nums, k) {
+  let ans = 0
+  let temp = new Array(32).fill(0)
+
+  let l = 0
+  for (let r = 0; r < nums.length; r++) {
+    for (let i = 0; i < 32; i++) {
+      if ((1 << i) & nums[r]) {
+        temp[i]++
+      }
+    }
+
+    while (r - l + 1 > 0 && calc(temp, r - l + 1) < k) {
+      for (let i = 0; i < 32; i++) {
+        if ((1 << i) & nums[l]) {
+          temp[i]--
+        }
+      }
+      l++
+    }
+    ans += r - l + 1
+  }
+
+  return ans
+}
+
+// function to calculate the AND from frequency vector
+function calc(temp, w) {
+  let ans = 0
+  for (let i = 0; i < 32; i++) {
+    if (temp[i] === w) {
+      ans += 1 << i
+    }
+  }
+
+  return ans
+}