Egqawkq的博客

Given a stringSand a stringT, count the number of distinct subsequences ofSwhich equalsT. A subsequence of a string is a new string which is formed from the original string by deleting some (ca...

题意：给一二叉树，对于非叶子节点可以交换左右孩子结点，从而形成了新的树，继而每个结点代表的字符串打乱顺序，问你给你两个字符串s1与s2，问s2是否可以由s1做上述操作得到。 Below is one possible representation ofs1="great": great / \ gr eat / \ / \ g r e ...

123.Best Time to Buy and Sell Stock III Say you have an array for which theithelement is the price of a given stock on dayi. Design an algorithm to find the maximum profit. You may complete at m...

其实这种两个字符串的操作题比较多，很多都是可以借助DP解决的，比较经典的题就比如：距离编辑 废话不多，dp[i][j]定义为s1的前i项以及s2前j项共同交叉组成了s3的前i+j项的可能性，只有满足组成条件时次可以设dp[i][j]=true 转移方程： i!=0&&j!=0: dp[i][j]=(dp[i-1][j]&&(s1[i-1]==s3[i+j-1]...

class Solution { private: void helper(TreeNode*root, TreeNode*&pre, vector<TreeNode*>&res) { if (root == NULL) return; helper(root->left, pre, res...

135.Candy # Share # There are N children standing in a line. Each child is assigned a rating value. # # You are giving candies to these children subjected to the following requirements: # # Each c...