190688/what-is-the-fastest-way-to-transpose-a-matrix-in-c
I have a reasonably large matrix that I need to transpose.
Assume, for example, that my matrix is
a b c d e f g h i j k l m n o p q r
I want the result be as follows:
a g m b h n c I o d j p e k q f l r
What is the fastest way to do this?
The ordered and unordered map containers (std::map and std::unordered map) are included in the standard library. The items in an ordered map are sorted by key, and insert and access are in O (log n). For ordered maps, the standard library often use red black trees. However, this is only an implementation detail. Insert and access are in O in an unordered map (1). It is simply another term for a hashtable. An illustration using (ordered) std::map: #include <map> #include <iostream> #include <cassert> int main(int argc, char ...READ MORE
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Use make heap() and its buddies from algorithm>, or priority queue from queue>. Make heap and friends are used by priority queue. #include <queue> // functional,iostream,ctime,cstdlib using namespace std; int main(int ...READ MORE
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fprintf is a polymorphism function in the C programming language. It can print to a file, stdout, a printer, a socket, or whatever else the system can represent as a stream if you supply it different handles. FILE* file = fopen("output.txt", "w"); ...READ MORE
Unordered sets must compensate for their O(1) ...READ MORE
I done some research about this. The ...READ MORE
Both std::lower bound and std::upper bound must have an increasing (non-decreasing) order as their objective. By giving a comparator as the 4th parameter of the functions, you may modify the meaning of "growing." To work with descending vectors, use std::greater. #include<iostream> #include<vector> #include<algorithm> #include<functional> using namespace std; int main() { ...READ MORE
What's the point of sorting your array? ...READ MORE
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