Merge pull request #3641 from austin-weeks/main

Create 0438-find-all-anagrams-in-a-string.ts

Author: Ykhan799

Diff for: typescript/0438-find-all-anagrams-in-a-string.ts

@@ -0,0 +1,33 @@
+//Time Complexity -> O(n)
+//Space Complexity -> O(n)
+function findAnagrams(s: string, p: string): number[] {
+  if (p.length > s.length) return [];
+
+  const anagramIndexes: number[] = [];
+  const pCount = new Map<string, number>();
+  const sCount = new Map<string, number>();
+  for (const char of p) pCount.set(char, (pCount.get(char) || 0) + 1);
+  for (let i = 0; i < p.length; i++) sCount.set(s[i], (sCount.get(s[i]) || 0) + 1);
+
+  let l = 0;
+  let r = p.length - 1;
+  while (r < s.length) {
+    let isAnagram = true;
+    for (const [char, count] of pCount) {
+      if (!sCount.has(char) || sCount.get(char) !== count) {
+        isAnagram = false;
+        break;
+      }
+    }
+    if (isAnagram) anagramIndexes.push(l);
+
+    sCount.set(s[l], (sCount.get(s[l]) || 1) - 1);
+    if (sCount.get(s[l]) === 0) sCount.delete(s[l]);
+    l++;
+
+    r++;
+    sCount.set(s[r], (sCount.get(s[r]) || 0) + 1);
+  }
+
+  return anagramIndexes;
+}