Merge branch 'main' of https://github.com/neetcode-gh/leetcode into mirvin/move-python-sols-to-dir

mitchellirvin · mitchellirvin · commit 93c6a9b21a32 · 2022-07-08T23:14:27.000-04:00
diff --git a/java/271-Encode-and-Decode-Strings.java b/java/271-Encode-and-Decode-Strings.java
@@ -2,32 +2,27 @@ public class Solution {
 
     public String encode(List<String> strs) {
         StringBuilder encodedString = new StringBuilder();
-        for(String str: strs){
-            int length = str.length();
-            encodedString.append(length+"#");
-            encodedString.append(str);
+        for (String str : strs) {
+            encodedString.append(str.length())
+                    .append("#")
+                    .append(str);
         }
         return encodedString.toString();
     }
 
     public List<String> decode(String str) {
-        List<String> decodedStrings = new ArrayList();
-        for(int i =0;i<str.length();i++){
-            String length = "";
-            while(str.charAt(i) != '#'){
-                length += str.charAt(i);
-                i++;
-            }
-            int wordLength = Integer.parseInt(length);
-            i++;
 
-            String word = "";
-            for(int j=i;j<wordLength+i;j++){
-                word += str.charAt(j);
-            }
-            decodedStrings.add(word);
-            i=i+wordLength-1;
+        List<String> list = new ArrayList<>();
+        int i = 0;
+        while (i < str.length()) { 
+            int j = i;
+            while (str.charAt(j) != '#')
+                j++;
+
+            int length = Integer.valueOf(str.substring(i, j));
+            i = j + 1 + length;
+            list.add(str.substring(j + 1, i));
         }
-        return decodedStrings;
+        return list;
     }
 }
diff --git a/javascript/739-daily-temperatures.js b/javascript/739-daily-temperatures.js
@@ -0,0 +1,19 @@
+/**
+ * @param {number[]} temperatures
+ * @return {number[]}
+ */
+const dailyTemperatures = function(temperatures) {
+    const output = Array(temperatures.length).fill(0)
+    
+    const stack = []
+    
+    for (let i = 0; i < temperatures.length; i++) {
+        while (stack.length !== 0 && stack[stack.length - 1][0] < temperatures[i]) {
+            const [temp, idx] = stack.pop()
+            output[idx] = i - idx
+        }
+        stack.push([temperatures[i], i])
+    }
+    
+    return output
+};
diff --git a/python/49-Group-Anagrams.py b/python/49-Group-Anagrams.py
@@ -1,10 +1,7 @@
 class Solution:
     def groupAnagrams(self, strs: List[str]) -> List[List[str]]:
-        ans = collections.defaultdict(list)
-        
+        hashmap = defaultdict(list)
         for s in strs:
-            count = [0] * 26
-            for c in s:
-                count[ord(c) - ord('a')] += 1
-            ans[tuple(count)].append(s)
-        return ans.values()
+            # keys can be strings, bcz they are immutable.
+            hashmap[str(sorted(s))].append(s) 
+        return hashmap.values()
diff --git a/typescript/217-Contains-Duplicate.ts b/typescript/217-Contains-Duplicate.ts
@@ -0,0 +1,10 @@
+function containsDuplicate(nums: number[]): boolean {
+  const set = new Set();
+
+  for (let i = 0; i < nums.length; i++) {
+    if (set.has(nums[i])) return true;
+    else set.add(nums[i]);
+  }
+
+  return false;
+}
diff --git a/typescript/242-Valid-Anagrams.ts b/typescript/242-Valid-Anagrams.ts
@@ -0,0 +1,16 @@
+function isAnagram(s: string, t: string): boolean {
+  if (s.length !== t.length) return false;
+
+  const store = new Array(26).fill(0);
+
+  for (let i = 0; i < s.length; i++) {
+    store[s.charCodeAt(i) - 'a'.charCodeAt(0)]++;
+    store[t.charCodeAt(i) - 'a'.charCodeAt(0)]--;
+  }
+
+  for (let i = 0; i < store.length; i++) {
+    if (store[i] !== 0) return false;
+  }
+
+  return true;
+}
