Create 953-verifying-an-alien-dictionary.js

Author: everthis

953-verifying-an-alien-dictionary.js

@@ -0,0 +1,27 @@
+/**
+ * @param {string[]} words
+ * @param {string} order
+ * @return {boolean}
+ */
+const isAlienSorted = function(words, order) {
+  const mapping = Array(26).fill(0), a = 'a'.charCodeAt(0)
+  for(let i = 0, len = order.length; i < len; i++) {
+    mapping[order.charCodeAt(i) - a] = i
+  }
+
+  for(let i = 1, n = words.length; i < n; i++) {
+    if(bigger(words[i - 1], words[i])) return false
+  }
+  
+  return true
+  
+  function bigger(s1, s2) {
+    const n = s1.length, m = s2.length;
+    for (let i = 0; i < n && i < m; ++i) {
+      if (s1.charAt(i) != s2.charAt(i)) return mapping[s1.charCodeAt(i) - a] > mapping[s2.charCodeAt(i) - a];          
+    }
+
+    return n > m;
+  }
+
+};