topic description Mathematical Combinatorial problems sources of topics and their own ideas competitive programs what result do you expect? What is the error message actually seen? I tried a way to solve this problem in O (n). But get the wron...
I did a question on leetcode, but for the string type, the push_back concatenation character failed the test, but changed to the plus sign to concatenate the character and passed it. topic link my two codes: class Solution { public: vector<...