[leet] string, trie (easy)

Author: hyeonbinHur

허현빈/8주차/lengthOfLastWord.js

@@ -0,0 +1,18 @@
+/**
+ * @param {string} s
+ * @return {number}
+ */
+var lengthOfLastWord = function(s) {
+    let stack = [];
+    const newS = s.trim()
+    for(let i = 0; i <newS.length; i++ ){
+        const val = newS[i]
+        if(val === ' '){
+            stack = []
+        }else{
+            stack.push(val)
+        }
+    }
+    return stack.length
+    
+};

허현빈/8주차/longestCommonPrefix-1.js

@@ -0,0 +1,13 @@
+/**
+ * @param {string[]} strs
+ * @return {string}
+ */
+var longestCommonPrefix = function(strs) {
+    let prefix = strs[0]
+    for(let i = 1; i < strs.length ; i++){
+        while(strs[i].indexOf(prefix) !== 0){
+            prefix = prefix.substring(0, prefix.length-1)
+        }
+    }
+    return prefix
+};

허현빈/8주차/longestCommonPrefix-2.js

@@ -0,0 +1,45 @@
+/**
+ * @param {string[]} strs
+ * @return {string}
+ */
+var longestCommonPrefix = function (strs) {
+  if (!strs || strs.length === 0) return "";
+  if (strs.length === 1) return strs[0];
+
+  class TrieNode {
+    constructor() {
+      this.children = new Map(); 
+      this.isEnd = false;
+      this.passCount = 0; 
+    }
+  }
+
+  const root = new TrieNode();
+
+  for (const word of strs) {
+    let node = root;
+    for (const ch of word) {
+      if (!node.children.has(ch)) {
+        node.children.set(ch, new TrieNode());
+      }
+      node = node.children.get(ch);
+      node.passCount += 1;
+    }
+    node.isEnd = true;
+  }
+
+  let node = root;
+  let prefix = "";
+
+  while (node.children.size === 1) {
+    const [[ch, next]] = node.children.entries();
+
+    if (next.passCount !== strs.length) break;
+
+    prefix += ch;
+    node = next;
+    if (node.isEnd) break;
+  }
+
+  return prefix;
+};