vector

问题 I am solving a problem on LeetCode, but nobody has yet been able to explain my issue. The problem is as such: Given an arbitrary ransom note string and another string containing letters from all the magazines, write a function that will return true if the ransom note can be constructed from the magazines ; otherwise, it will return false. Each letter in the magazine string can only be used once in your ransom note. Note: You may assume that both strings contain only lowercase letters.

问题 I am solving a problem on LeetCode, but nobody has yet been able to explain my issue. The problem is as such: Given an arbitrary ransom note string and another string containing letters from all the magazines, write a function that will return true if the ransom note can be constructed from the magazines ; otherwise, it will return false. Each letter in the magazine string can only be used once in your ransom note. Note: You may assume that both strings contain only lowercase letters.

问题 I would like to know if it's possible to have multiple while (cin>>(variable)) as in the following code: #include <iostream> #include <vector> using namespace std; int main() { vector<int> v1, v2; int input; while (cin>>input) v1.push_back(input); while (cin>>input) v2.push_back(input); return 0; } The logic of my program is to let user define the number of elements and value of each element in two sets of int vectors. However, I realized that after entering the first set of numbers for the

问题 I would like to know if it's possible to have multiple while (cin>>(variable)) as in the following code: #include <iostream> #include <vector> using namespace std; int main() { vector<int> v1, v2; int input; while (cin>>input) v1.push_back(input); while (cin>>input) v2.push_back(input); return 0; } The logic of my program is to let user define the number of elements and value of each element in two sets of int vectors. However, I realized that after entering the first set of numbers for the

问题 I would like to know if it's possible to have multiple while (cin>>(variable)) as in the following code: #include <iostream> #include <vector> using namespace std; int main() { vector<int> v1, v2; int input; while (cin>>input) v1.push_back(input); while (cin>>input) v2.push_back(input); return 0; } The logic of my program is to let user define the number of elements and value of each element in two sets of int vectors. However, I realized that after entering the first set of numbers for the

问题 My base class: class Item { protected: int count; string model_name; int item_number; public: Item(); void input(); } My derived Class: class Bed : public Item { private: string frame; string frameColour; string mattress; public: Bed(); void input(); } for now all my input function is trying to do is output which method is being used: void Item::input() { cout<<"Item input"<<endl; } void Bed::input() { cout<<" Bed Input"<<endl; } when I call the function in main I'd like the derived class

问题 I have a text file that has values and I want to put them into a 2D vector. I can do it with arrays but I don't know how to do it with vectors. The vector size should be like vector2D[nColumns][nLines] that I don't know in advance. At the most I can have in the text file the number of columns, but not the number of lines. The number of columns could be different, from one .txt file to another. .txt example: 189.53 -1.6700 58.550 33.780 58.867 190.13 -3.4700 56.970 42.190 75.546 190.73 -1.3000

问题 Let class Record { public: Record(); private: string id; double score; }; Somewhere we define a vector of Record objects, i.e., vector<Record> records(N); // Initialize records somehow I would like to sort records based on score (in descending order) keeping track of the other member variables of Record (in this case just the score , but in general whatever else). 回答1: You can implement the comparison operators. bool Record::operator<(const Record& rhs) { return score < rhs.score; } bool

问题 I was looking through some STL documentation. I see that the syntax for a priority queue which stores in a descending order is: std::priority_queue<int> q ; //gives 9 8 7 6 5 4 3 2 1 when pushed and obtained However, for storing in an ascending fashion, it's: std::priority_queue< int, std::vector<int>, std::greater<int> > q ; //gives 1 2 3 4 5 6 7 8 9 when pushed and obtained I want to know what are the specific uses of the extra template parameters in the second example. As in, what does std

问题 I was looking through some STL documentation. I see that the syntax for a priority queue which stores in a descending order is: std::priority_queue<int> q ; //gives 9 8 7 6 5 4 3 2 1 when pushed and obtained However, for storing in an ascending fashion, it's: std::priority_queue< int, std::vector<int>, std::greater<int> > q ; //gives 1 2 3 4 5 6 7 8 9 when pushed and obtained I want to know what are the specific uses of the extra template parameters in the second example. As in, what does std