[ PS ] : Missing Number

Author: uraflower

missing-number/uraflower.js

@@ -0,0 +1,17 @@
+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+const missingNumber = function(nums) {
+    const n = nums.length;
+    let sum = (n * (n + 1)) / 2;
+
+    for (let num of nums) {
+        sum -= num;
+    }
+    
+    return sum;
+};
+
+// 시간복잡도: O(n)
+// 공간복잡도: O(1)