Create 1442-count-triplets-that-can-form-two-arrays-of-equal-xor.js

Author: everthis

1442-count-triplets-that-can-form-two-arrays-of-equal-xor.js

@@ -0,0 +1,20 @@
+/**
+ * @param {number[]} arr
+ * @return {number}
+ */
+const countTriplets = function(arr) {
+  arr.unshift(0)
+  const n = arr.length
+  let res = 0
+  for(let i = 1; i < n; i++) {
+    arr[i] ^= arr[i - 1]
+  }
+  const count = {}, total = {}
+  for(let i = 0; i < n; i++) {
+    if(count[arr[i]] == null) count[arr[i]] = 0
+    if(total[arr[i]] == null) total[arr[i]] = 0
+    res += count[arr[i]]++ * (i - 1) - total[arr[i]]
+    total[arr[i]] += i
+  }
+  return res
+};