From caaa5b0e2734df35d648a77baaf7660463169070 Mon Sep 17 00:00:00 2001
From: ductnn <trannhuduc531998@gmail.com>
Date: Tue, 20 Feb 2024 22:24:17 +0700
Subject: [PATCH] add sol

---
 leetcode/268.MissingNumber/missingNumber.go | 39 +++++++++++++++++++++
 1 file changed, 39 insertions(+)
 create mode 100644 leetcode/268.MissingNumber/missingNumber.go

diff --git a/leetcode/268.MissingNumber/missingNumber.go b/leetcode/268.MissingNumber/missingNumber.go
new file mode 100644
index 0000000..fb55838
--- /dev/null
+++ b/leetcode/268.MissingNumber/missingNumber.go
@@ -0,0 +1,39 @@
+// https://leetcode.com/problems/missing-number/
+
+package main
+
+import (
+	"fmt"
+)
+
+func missingNumber(nums []int) int {
+	n := len(nums)
+	sum := 0
+	for _, v := range nums {
+		sum += v
+	}
+
+	return n*(n+1)/2 - sum
+}
+
+func missingNumber1(nums []int) int {
+	n := len(nums)
+	m := make([]bool, n+1)
+
+	for _, v := range nums {
+		m[v] = true
+	}
+
+	for i, exists := range m {
+		if !exists {
+			return i
+		}
+	}
+
+	return 0
+}
+
+func main() {
+	nums := []int{9, 6, 4, 2, 3, 5, 7, 0, 1}
+	fmt.Println(missingNumber1(nums))
+}