[eunice-hong] WEEK 02 solutions

climbing-stairs/eunice-hong.ts

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+function climbStairs(n: number): number {
+  // memoization to store the results of the subproblems
+  const memo = new Map();
+
+  // if n is 1 or 2, return n
+  memo.set(1, 1);
+  memo.set(2, 2);
+
+  // recursive function to calculate the number of ways to climb the stairs
+  function climb(n: number, memo: Map<number, number>): number {
+    let result = memo.get(n);
+    if (result) {
+      return result;
+    } else {
+      result = climb(n - 1, memo) + climb(n - 2, memo);
+      memo.set(n, result);
+      return result;
+    }
+  }
+
+  return climb(n, memo);
+}

valid-anagram/eunice-hong.ts

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+function isAnagram(s: string, t: string): boolean {
+  // if the length of the two strings are not the same, return false
+  if (s.length !== t.length) return false;
+
+  // create a map of the characters in string s and t
+  const sMap = new Map();
+  const tMap = new Map();
+
+  // iterate through the strings and add the characters to the maps
+  for (let i = 0; i < s.length; i++) {
+    sMap.set(s[i], (sMap.get(s[i]) ?? 0) + 1);
+    tMap.set(t[i], (tMap.get(t[i]) ?? 0) + 1);
+  }
+
+  // if the values of the maps are not the same, return false
+  for (let char of sMap.keys()) {
+    if (sMap.get(char) !== tMap.get(char)) {
+      return false;
+    }
+  }
+  return true;
+}