In this lecture, we will address an algorithm problem that involves implementing an absolute value heap. This problem is one of the frequently asked types in C++ programming and can be solved using a priority queue. An absolute value heap is a data structure that sorts based on the absolute value of a specific number.<\/p>\n
An absolute value heap supports the following operations:<\/p>\n
The first line contains the number of operations Print the results of the delete operations, one per line.<\/p>\n To solve this problem, we will use a priority queue. The C++ standard library provides To implement the absolute value heap, we will define the following comparison function:<\/p>\n Based on the above comparison function, we can define the priority queue and perform insert and delete operations.<\/p>\n The above C++ code implements the absolute value heap:<\/p>\nN<\/code> (1 \u2264 N<\/code> \u2264 100,000). The next N<\/code> lines contain the operations to be performed. The operations are divided into two types:<\/p>\n\n
Insert<\/code>: 0<\/code> x<\/code> (\u2212109<\/sup> \u2264 x<\/code> \u2264 109<\/sup>) format, which inserts x<\/code> into the absolute value heap.<\/li>\nDelete<\/code>: specified with 0<\/code>, removes and returns the integer with the smallest absolute value from the absolute value heap.<\/li>\n<\/ul>\nOutput<\/h3>\n
Example Input<\/h2>\n
\n10\n1\n-1\n0\n1\n0\n-1\n0\n0\n0\n0\n<\/pre>\n
Example Output<\/h2>\n
\n-1\n1\n0\n0\n0\n<\/pre>\n
Approach to the Problem<\/h2>\n
std::priority_queue<\/code>, which operates as a max heap by default. However, we need to create a min heap based on absolute values. Therefore, we will customize std::priority_queue<\/code> to implement this.<\/p>\nHeap Implementation<\/h3>\n
\nstruct Compare {\n bool operator()(int a, int b) {\n if (abs(a) == abs(b)) {\n return a > b; \/\/ Choose the smaller value if the absolute values are the same\n }\n return abs(a) > abs(b); \/\/ Choose based on absolute value\n }\n};\n<\/pre>\nC++ Code Implementation<\/h2>\n
\n#include
Code Explanation<\/h2>\n