LintCode

C++11 Solution to LintCode websites Some solutions source from http://www.jiuzhang.com/solutions/ and https://github.com/kamyu104/LintCode

• In C++, there is no need to apply "a == NULL", we can apply if (a) or if (!a)to test a is exit or not.

• When we assign / equal two ListNodes, we should apply:

    ListNode (star)cur = &dummy.

• In C++, the pop function of the queue will not return anything.

• We can use (const auto& word : words) to save the defintion on date type of word.

• In C++, the map function on hasKey / containsKey equal to count().

• Check Soltuion on Union-find.

• Use !lookup.emplace(sum, i).second if make a decision on whether this map has this key or not.

• In C++, we transform string to a stringstream, and use getline to split this string by delim (WTF).

• When we want to create a const size of vector, we use

vector list(10);

• When we create a 2D matrix, we use:

vector<vector<int>> matrix(2, vector<int>(10, dafualt value));

• When we would like to use priority queue in C++:

    struct Compare {
        bool operator()(const Cell& a, const Cell& b) {
            return a.height > b.height;
        }
    };
        struct Cell {
        int i;
        int j;
        int height;
    };
    vector<vector<bool>> is_visited_ = vector<vector<bool>>(m_, vector<bool>(n_, false));
    priority_queue<Cell ,vector<Cell>, Compare> heap_;

• When we want to add string in c++:

	stringstream ss;
	ss << str1 << str2;
	return ss.str();

• When we use map, we can use map[key] to get value (same as Python).

• In the simple array, we can new as:

double balance[5] = {1.0, 2.0, 3.4, 17.9, 39.4};

• If we use new / delete method, new as:

long * res = new long[n]; delete res;

• Remeber, the substr in C++ is different from JAVA, and we should define that new string is: oldString.substr(start, end - start + 1); the second argument is length of new string.

• lower_bound in C++, excited.

• C++ erase method, vector.erase(nums.begin() + index);

• static_cast is able to perform with pointers to classes not only the conversions allowed implicitly, but also their opposite conversions.

• The aim of UNION in C/C++ is to save the data space in apply class or struct.

• If we are asked to consider of 32 bits in C++, we should use left_part >= 31 to make sure we overrange or not.

• When we construct a tree node, we should perform Clone method to aviod pass-by-value issue.

• The node copy/sepeter template is in Copy List with Random Pointer.cpp.

• Use & at parameter of function to make sure it can be updated all the time.

• Upper and Lower bound method template in C++ is in Search for a Range.cpp.

• The 1/k major number solution template is located in Majority Number II & III.cpp.

• We can also use foo (int * num) as function describition, and foo(&x); to perform pass-by-referencce.

• KMP algorithm implement in C++ lcoated in strStr.cpp file.

• There are four important steps to perform debug / write unit test methods.

  • Does any variables types are correct, does they are all defined before call
  • Does this method can finish its task? does it will end at its wish.
  • Does it return the correct data, and modify the correct data.
  • Does it handle the special input.

Amazone Web Services

This tutorial used to learn how to install program in cloud-platform, and manage Amazon storage.

• We use AWS Identity and Access Management (IAM) to access AWS how to create IAM. By this approach, we can create a user list to control access to different kinds of users.