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

javascript/0438-find-all-anagrams-in-a-string.js

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+/**
+ * @param {string} s
+ * @param {string} p
+ * @return {number[]}
+ */
+var findAnagrams = function (s, p) {
+ const charMap = new Map();
+ let matches = 0;
+ const matchIdx = [];
+
+ for (const char of p) {
+ const charCount = charMap.get(char) || 0;
+ charMap.set(char, charCount + 1);
+ }
+
+ let leftWindow = 0;
+ for (let rightWindow = 0; rightWindow < s.length; rightWindow++) {
+ const rightChar = s[rightWindow];
+ if (charMap.has(rightChar)) {
+ const rightCharCount = charMap.get(rightChar);
+ charMap.set(rightChar, rightCharCount - 1);
+ if (charMap.get(rightChar) === 0) {
+ matches++;
+ }
+ }
+ if (rightWindow >= p.length) {
+ const leftChar = s[leftWindow];
+ if (charMap.has(leftChar)) {
+ const leftCharCount = charMap.get(leftChar);
+ charMap.set(leftChar, leftCharCount + 1);
+ if (leftCharCount === 0) {
+ matches--;
+ }
+ }
+ leftWindow++;
+ }
+ if (matches === charMap.size) {
+ matchIdx.push(leftWindow);
+ }
+ }
+ return matchIdx;
+};