Classic

304. Range Sum Query 2D - Immutable

304. Range Sum Query 2D - Immutable 解題方式同: 303. Range

210. Course Schedule II

210. Course Schedule II Check 207. Course Schedule

207. Course Schedule

207. Course Schedule 這一個題目的設計滿巧秒的,我個人覺得這個題目綜合了樹的遍歷(遞迴)、回溯法、動態規劃以及資料與圖形轉換的設計,外加上題目可以套用在各種現實生活問題中。所以整體而言

1676. Lowest Common Ancestor of a Binary Tree IV

1676. Lowest Common Ancestor of a Binary Tree IV Check

1650. Lowest Common Ancestor of a Binary Tree III

1650. Lowest Common Ancestor of a Binary Tree III Check

1644. Lowest Common Ancestor of a Binary Tree II

1644. Lowest Common Ancestor of a Binary Tree II Check

236. Lowest Common Ancestor of a Binary Tree

236. Lowest Common Ancestor of a Binary Tree Check 235.

235. Lowest Common Ancestor of a Binary Search Tree

* 235. Lowest Common Ancestor of a Binary Search Tree * 236.

18. 4 Sum

18. 4 Sum Check 15. 3 Sum

5. Longest Palindromic Substring

5. Longest Palindromic Substring 這一題是我們要找出子字串中的最長的回文,其實最好從暴力解法開始學習起,前面的題目已經重複提過了好多次的回文的性質,這裡就用暴力法先來思考以下。 暴力法 (TLE)