go: add «1442. Count Triplets That Can Form Two Arrays of Equal XOR»

Signed-off-by: Matej Focko <me@mfocko.xyz>

go/count-triplets-that-can-form-two-arrays-of-equal-xor.go

@@ -0,0 +1,26 @@
+package count_triplets_that_can_form_two_arrays_of_equal_xor
+
+func countTriplets(arr []int) int {
+	precomputePrefix := func() []int {
+		prefix := append([]int{0}, arr...)
+
+		for i, _ := range arr {
+			prefix[i+1] ^= prefix[i]
+		}
+
+		return prefix
+	}
+
+	prefix := precomputePrefix()
+
+	triplets := 0
+	for left, _ := range prefix {
+		for right := left + 1; right < len(prefix); right++ {
+			if prefix[left] == prefix[right] {
+				triplets += right - left - 1
+			}
+		}
+	}
+
+	return triplets
+}