Add week 4 solutions: missing-number

Author: gitsunmin

missing-number/gitsunmin.ts

@@ -0,0 +1,12 @@
+/**
+ * https://leetcode.com/problems/missing-number
+ * time complexity : O(n)
+ * space complexity : O(n)
+ */
+function missingNumber(nums: number[]): number {
+    const set = new Set<number>(nums);
+
+    for (let i = 0; i < set.size + 1; i++) if (!set.has(i)) return i;
+
+    return 0;
+};