Missing Number

Author: hyejjun

missing-number/hyejjun.js

@@ -0,0 +1,21 @@
+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+var missingNumber = function (nums) {
+  let n = nums.length;
+  let expectedSum = n * (n + 1) / 2;
+
+  let actualSum = nums.reduce((acc, curr) => acc + curr, 0);
+
+  return expectedSum - actualSum;
+};
+
+console.log(missingNumber([3, 0, 1]));
+console.log(missingNumber([0, 1]));
+console.log(missingNumber([9, 6, 4, 2, 3, 5, 7, 0, 1]));
+
+/*
+시간 복잡도: O(n)
+공간 복잡도: O(1)
+*/