add: 220215 [golang]

2202/220215.go

@@ -0,0 +1,16 @@
+package main
+
+import "fmt"
+
+func singleNumber(nums []int) int {
+	var x = 0
+	for _, v := range nums {
+		x ^= v
+	}
+	return x
+}
+
+func main() {
+	var args = []int{4, 1, 2, 1, 2}
+	fmt.Println(singleNumber(args))
+}