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Problem Description Write a function that reverses a string. The input string is given as an array of characters char[]. Do not allocate extra space for another array, you must do this by modifying the input array in-place with O(1) extra memory. You may

Problem Description There are 2N people a company is planning to interview. The cost of flying the i-th person to city A is costs[i][0], and the cost of flying the i-th person to city B is costs[i][1]. Return the minimum cost to fly every person to a city

其实这次没太看懂题目啊 那个函数输入的是要删除的节点还是头节点啊好郁闷 就当作删除的节点来写了没想到ok的？（小声 啊数据结构这玩意真的该复习一波了orz Problem Description Write a function to delete a node (except the tail) in a singly linked list, given only access to that node. /** * Definition for singly-linked list. * stru

<c艹复健期间 改用c艹刷leetcode> Invert Binary Tree Problem Description Solution 遍历树的话就前序遍历，先访问根节点再左子树然后右子树。对左右节点进行交换，就设一个中间量然后互换。（emmmmm好像没啥好说的就这样 void swap(TreeNode *curr) { if(!curr) return; swap(curr->left); swap(cu