js-concepts: leetcode prob.567 - permutation string

Author: baochau.dinh

LeetCode/567. Permutation in String/index.js

@@ -0,0 +1,29 @@
+var isPermutation = function(s1, s2) {
+  if (s1.length !== s2.length) return false;
+  
+  let hashMapOfS1 = {}, hashMapOfS2 = {};
+  for (let i = 0; i < s1.length; i++) {
+      hashMapOfS1[s1[i]] = hashMapOfS1[s1[i]] + 1 || 1;
+  }
+  for (let i = 0; i < s2.length; i++) {
+      hashMapOfS2[s2[i]] = hashMapOfS2[s2[i]] + 1 || 1;
+  }
+  
+  for (keys in hashMapOfS1) {
+      if (hashMapOfS1[keys] !== hashMapOfS2[keys]) return false;
+  }
+  
+  return true;
+}
+
+var checkInclusion = function(s1, s2) {
+  let permutationLength = s1.length;
+  let first = 0, second = permutationLength - 1;
+  while (first < s2.length && second < s2.length) {
+      let currentStr = s2.slice(first, second + 1);
+      if (isPermutation(s1, currentStr)) return true;
+      first++;
+      second++;
+  }
+  return false;
+};