Find all anagrams in a string

Author: charlesbuczel

0438_findAllAnagramsInAString.js

@@ -0,0 +1,38 @@
+/**
+ * @param {string} s
+ * @param {string} p
+ * @return {number[]}
+ */
+
+const isAnagram = (word, candidate) => {
+  if (word.length !== candidate.length) return false;
+
+  const charMap = {};
+  for (let index = 0; index < word.length; index++) {
+    if (word.indexOf(candidate[index]) < 0) {
+      return false;
+    }
+    charMap[word[index]] = charMap[word[index]] ? charMap[word[index]] + 1 : 1;
+    charMap[candidate[index]] = charMap[candidate[index]] ? charMap[candidate[index]] - 1 : -1;
+  }
+
+  return Object.keys(charMap).every(char => charMap[char] === 0);
+};
+
+const findAnagrams = (s, p) => {
+  const anagrams = {};
+  anagrams[p] = true;
+
+  const answer = [];
+
+  const length = s.length - p.length + 1;
+  for (let index = 0; index < length; index++) {
+    const candidate = s.slice(index, index + p.length);
+
+    if (anagrams[candidate] === undefined) anagrams[candidate] = isAnagram(p, candidate);
+
+    if (anagrams[candidate]) answer.push(index);
+  }
+
+  return answer;
+};