[yihyun-kim1] WEEK 02 Solutions

climbing-stairs/yihyun-kim1.js

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+/**
+ * @param {number} n
+ * @return {number}
+ */
+
+const climbStairs = (n) => {
+  if (n <= 2) return n;
+
+  let prev1 = 1;
+  let prev2 = 2;
+
+  for (let i = 3; i <= n; i++) {
+    const current = prev1 + prev2;
+    prev1 = prev2;
+    prev2 = current;
+  }
+
+  return prev2;
+};

valid-anagram/yihyun-kim1.js

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+/**
+ * @param {string} s
+ * @param {string} t
+ * @return {boolean}
+ */
+const isAnagram = (s, t) => {
+  if (s.length !== t.length) return false;
+
+  const map = new Map();
+
+  for (let char of s) {
+    map.set(char, (map.get(char) || 0) + 1);
+  }
+
+  for (let char of t) {
+    if (!map.has(char)) return false;
+    map.set(char, map.get(char) - 1);
+    if (map.get(char) < 0) return false;
+  }
+
+  return true;
+};