feat: add scramble string algorithm

String/ScrambleStrings.js

@@ -0,0 +1,50 @@
+// Problem Statement and Explanation: https://leetcode.com/problems/scramble-string/
+
+/**
+ * Given two strings s1 and s2 of the same length, return true if s2 is a scrambled string of s1, otherwise, return false.
+ * @param {string} s1
+ * @param {string} s2
+ * @return {boolean}
+ */
+
+const isScramble = (s1, s2) => {
+  return helper({}, s1, s2)
+}
+
+const helper = function (dp, s1, s2) {
+  const map = {}
+
+  if (dp[s1 + s2] !== undefined) return dp[s1 + s2]
+  if (s1 === s2) return true
+
+  for (let j = 0; j < s1.length; j++) {
+    if (map[s1[j]] === undefined) map[s1[j]] = 0
+    if (map[s2[j]] === undefined) map[s2[j]] = 0
+    map[s1[j]]++
+    map[s2[j]]--
+  }
+
+  for (const key in map) {
+    if (map[key] !== 0) {
+      dp[s1 + s2] = false
+      return false
+    }
+  }
+
+  for (let i = 1; i < s1.length; i++) {
+    if (
+      (helper(dp, s1.substr(0, i), s2.substr(0, i)) &&
+        helper(dp, s1.substr(i), s2.substr(i))) ||
+      (helper(dp, s1.substr(0, i), s2.substr(s2.length - i)) &&
+        helper(dp, s1.substr(i), s2.substr(0, s2.length - i)))
+    ) {
+      dp[s1 + s2] = true
+      return true
+    }
+  }
+
+  dp[s1 + s2] = false
+  return false
+}
+
+console.log(isScramble('great', 'rgeat'))