solve isomorphic-strings.js

Author: imcoddy

isomorphic-strings.js

@@ -0,0 +1,58 @@
+/**
+ * Source:  https://leetcode.com/problems/isomorphic-strings/
+ * Tags:    [Hash Table]
+ * Level:   Easy
+ * Title:   Isomorphic Strings
+ * Auther:  @imcoddy
+ * Content: Given two strings s and t, determine if they are isomorphic.
+ *
+ * Two strings are isomorphic if the characters in s can be replaced to get t.
+ *
+ * All occurrences of a character must be replaced with another character while preserving the order of characters. No two characters may map to the same character but a character may map to itself.
+ *
+ * For example,
+ * Given "egg", "add", return true.
+ *
+ * Given "foo", "bar", return false.
+ *
+ * Given "paper", "title", return true.
+ *
+ * Note:
+ * You may assume both s and t have the same length.
+ */
+
+/**
+ * @param {string} s
+ * @param {string} t
+ * @return {boolean}
+ */
+
+/**
+ * Memo:
+ * Runtime: 133ms
+ * Rank: A
+ */
+var isIsomorphic = function(s, t) {
+    var map_s = {};
+    var map_t = {};
+    var result = true;
+    for (var i = 0; i < s.length; i++) {
+        if (map_s[s[i]] || map_t[t[i]]) {
+            if (map_s[s[i]] !== t[i] || map_t[t[i]] !== s[i]) {
+                result = false;
+                break;
+            }
+        } else {
+            map_s[s[i]] = t[i];
+            map_t[t[i]] = s[i];
+        }
+    }
+
+    return result;
+};
+
+console.log(isIsomorphic('egg', 'add'));
+console.log(isIsomorphic('foo', 'bar'));
+console.log(isIsomorphic('paper', 'title'));
+console.log(isIsomorphic('ab', 'ca'));
+console.log(isIsomorphic('ab', 'aa'));