[seungseung88] WEEK 02 solutions

climbing-stairs/seungseung88.js

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+/**
+ * 시간복잡도: O(n)
+ *  - for문 O(n)
+ * 공간복잡도: O(n)
+ *  - arr O(n)
+ */
+const climbStairs = (n) => {
+  const arr = [1, 2];
+
+  for (let i = 2; i < n; i += 1) {
+    arr[i] = arr[i - 1] + arr[i - 2];
+  }
+
+  return arr[n - 1];
+};

valid-anagram/seungseung88.js

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+/**
+ * 시간복잡도: O(n)
+ *  - 첫번째 for문 O(n)
+ *  - 두번째 for문 최대 O(n)
+ * 공간복잡도: O(n)
+ *  - count O(n)
+ */
+
+const isAnagram = (s, t) => {
+  if (s.length !== t.length) return false;
+
+  const count = {};
+
+  for (let i = 0; i < s.length; i += 1) {
+    count[s[i]] = (count[s[i]] || 0) + 1;
+    count[t[i]] = (count[t[i]] || 0) - 1;
+  }
+
+  for (const i of Object.values(count)) {
+    if (i !== 0) return false;
+  }
+
+  return true;
+};