I update segment tree with such function. Profiling says here's the bottleneck:
void update (int tree[], int root, int left, int right, int pos, double val)
{
if (left == right)
{
data[tree[root]] = val;
}
else
{
int middle = (left + right) / 2;
if (pos <= middle)
update(tree, root*2, left, middle, pos, val);
else
update(tree, root*2+1, middle+1, right, pos, val);
tree[root] = indexOfMax(tree, tree[root*2], tree[root*2+1]); // simple comparations
}
}
// indexOfMax is just a simple comparation
int indexOfMax(int tree[], int a, int b)
{
//cout << data[tree[a]] << " > " << data[tree[b]] << " ? " << tree[a] << " : " << tree[b] << endl;
return data[a] > data[b] ? a : b;
}
And while memory operations are fast, I'm wondering if it is caused by recursion overhead, while the depth of it is usually not more 20.
What I get from my primitive profiler is:
4.39434ms - average time for a singe binary search over data
2642.94ms - time from a single update
19.9097ms - time for a single RMQ-query.
So.. The time spent on a single update is dramatic :).
Answer : one hidden std::find over map was found.
Related
int main(){
int V1;
float V2;
bool V3 = true;
int *Ptr1;
int *Ptr2;
*Ptr1 = V1;
*Ptr2 = V2;
cout << "Enter the worth of V1: " << endl;
cin >> *Ptr1;
cout << "Enter the worth of V2: " << endl;
cin >> *Ptr2;
int *Ptr3 = &Ptr1 - &Ptr2;
cout << Ptr3;
}
My problem is that when i declare the variables i have to put one float and one int, so the program don´t let me substract a float with an int.
int *Ptr1;
int *Ptr2;
*Ptr1 = V1;
*Ptr2 = V2;
This is undefined behavior. Ptr1 and Ptr2 are uninitialized, but you attempt to dereference them in the assignment statements. You are trying to write values into random (uninitialized) memory locations.
int *Ptr3 = &Ptr1 - &Ptr2;
Here you use the & operator to take the addresses of Ptr1 and Ptr2 (which are already pointers!), then try to subtract the addresses, and use
that to initialize Ptr3.
None of this makes any sense. You seem to be misunderstanding how pointers,
the & operator, and the * operator work. Better make another pass through whatever reference materials you're working from...
Im trying to highlight all the match words on the editor and can't seem to figure out how to properly highlight the text. I can successfully loop through all the found matches but cant seem to find the right call to highlight it. Here is my code:
bool found = true;
while(found)
{
editor->getCursorPosition(&line, &index);
qDebug() << "line: " << line << " index: " << index;
found = editor->findFirst(pattern, use_regular_expression, is_case_sensitive, match_whole_word_only, use_wrap, search_forward);
if(found)
{
int start = editor->positionFromLineIndex(line, index);
int end = editor->positionFromLineIndex(line, index + pattern.length());
qDebug() << "line: " << line << " start: " << start << " end: " << end;
// Attempts to highlight
editor->SendScintilla(QsciScintilla::SCI_INDICGETSTYLE, QsciScintilla::INDIC_BOX);
editor->SendScintilla(QsciScintilla::SCI_INDICSETFORE, 0x007f00);
//child[0]->SendScintilla(QsciScintilla::SCI_INDICATORFILLRANGE, start, end - start);
editor->SendScintilla(QsciScintilla::SCI_INDICATORFILLRANGE, start, end - start);
editor->setIndicatorForegroundColor(QColor(159, 144, 0));
// editor->setColor(QColor(159, 144, 0));**
}
}
my qDebug()'s is showing that its going through each line and finding the matches and the position of the occurance of the word. But code under the comment // Attempts to highlight is where I cant seem to figure out. Any advice?
You can try it.
SendScintilla(QsciScintillaBase::SCI_INDICSETSTYLE,0, INDIC_BOX);
QString docText = text();
int end = docText.lastIndexOf(findText);
int cur = -1;
if(end != -1) {
while(cur != end) {
cur = docText.indexOf(findText,cur+1);`
SendScintilla(QsciScintillaBase::SCI_INDICATORFILLRANGE,cur,
findText.length());
}
}
For the quick sort algorithm(recursive), every time when it calls itself, it have the condition if(p < r). Please correct me if I am wrong: as far as I know, for every recursive algorithm, it has a condition as the time when it entered the routine, and this condition is used to get the base case. But I still cannot understand how to correctly set and test this condition ?
void quickSort(int* arr, int p, int r)
{
if(p < r)
{
int q = partition(arr,p,r);
quickSort(arr,p,q-1);
quickSort(arr,q+1,r);
}
}
For my entire code, please refer to the following:
/*
filename : main.c
description: quickSort algorithm
*/
#include<iostream>
using namespace std;
void exchange(int* val1, int* val2)
{
int temp = *val1;
*val1 = *val2;
*val2 = temp;
}
int partition(int* arr, int p, int r)
{
int x = arr[r];
int j = p;
int i = j-1;
while(j<=r-1)
{
if(arr[j] <= x)
{
i++;
// exchange arr[r] with arr[j]
exchange(&arr[i],&arr[j]);
}
j++;
}
exchange(&arr[i+1],&arr[r]);
return i+1;
}
void quickSort(int* arr, int p, int r)
{
if(p < r)
{
int q = partition(arr,p,r);
quickSort(arr,p,q-1);
quickSort(arr,q+1,r);
}
}
// driver program to test the quick sort algorithm
int main(int argc, const char* argv[])
{
int arr1[] = {13,19,9,5,12,8,7,4,21,2,6,11};
cout <<"The original array is: ";
for(int i=0; i<12; i++)
{
cout << arr1[i] << " ";
}
cout << "\n";
quickSort(arr1,0,11);
//print out the sorted array
cout <<"The sorted array is: ";
for(int i=0; i<12; i++)
{
cout << arr1[i] << " ";
}
cout << "\n";
cin.get();
return 0;
}
Your question is not quite clear, but I will try to answer.
Quicksort works by sorting smaller and smaller arrays. The base case is an array with less than 2 elements because no sorting would be required.
At each step it finds a partition value and makes it true that all the values to the left of the partition value are smaller and all values to the right of the partition value are larger. In other words, it puts the partition value in the correct place. Then it recursively sorts the array to the left of the partition and the array to right of the partition.
The base case of quicksort is an array with one element because a one element array requires no sorting. In your code, p is the index of the first element and r is the index of the last element. The predicate p < r is only true for an array of at least size 2. In other words, if p >= r then you have an array of size 1 (or zero, or nonsense) and there is no work to do.
Queue class
#ifndef Queue_H
#define Queue_H
#include "Car.h"
#include <iostream>
#include <string>
using namespace std;
const int Q_MAX_SIZE = 20;
class Queue {
private:
int size; // size of the queue
Car carQueue[Q_MAX_SIZE];
int front, rear;
public:
Queue();
~Queue();
bool isEmpty();
bool isFull();
void enqueue(Car c);
void dequeue(); // just dequeue the last car in the queue
void dequeue(Car c); // if a certain car wants to go out of the queue midway.
// Condition: Car is not in washing. Meaning is not the 1st item in the queue
void dequeue(int index); // same as the previous comment
Car getFront();
void getCarQueue(Queue);
int length();
Car get(int);
};
Queue::Queue() {
size = 0;
front = 0;
rear = Q_MAX_SIZE -1;
}
Queue::~Queue() {
while(!isEmpty()) {
dequeue();
}
}
void Queue::enqueue(Car c) {
if (!isFull()) {
rear = (rear + 1) % Q_MAX_SIZE; // circular array
carQueue[rear] = c;
size++;
} else {
cout << "Queue is currently full.\n";
}
}
void Queue::dequeue() {
}
void Queue::dequeue(int index) {
if(!isEmpty()) {
front = (front + 1) % Q_MAX_SIZE;
if(front != index) {
carQueue[index-1] = carQueue[index];
rear--;
size--;
} else {
cout << "Not allowed to dequeue the first car in the queue.\n";
}
} else {
cout << "There are no cars to dequeue.\n";
}
}
bool Queue::isEmpty() {
return size == 0;
}
bool Queue::isFull() {
return (size == Q_MAX_SIZE);
}
Car Queue::getFront() {
return carQueue[front];
}
int Queue::length() {
return size;
}
Car Queue::get(int index) {
return carQueue[index-1];
}
void Queue::getCarQueue(Queue q) {
for(int i = 0; i< q.length(); i++)
cout << q.get(i) << endl; // Error here
}
#endif
error C2679: binary '<<' : no operator found which takes a right-hand operand of type 'Car' (or there is no acceptable conversion)
I get this error which is kind of odd. so is there anything wrong? Thanks!
cout has no idea how to process a car object; it has never seen a car object and doesn't know how you output a car as text. cout can only process types it knows about, string, char, int, etc. The specific error is because there is version of operator << that takes an ostream and a car.
There are two options:
Creation an overload for operator<< that takes an ostream and a car. That will show cout how to output a car. This isn't usually done becuase there is usually more than one way your would want to display a car.
Write the output statement so that it manually prints out car properties like
cout << c.getMake() << " " << c.getModel()
I am a novice C++ coder and obviously not very good at it. I am having an immense amount of trouble with this program.
I am getting syntax errors on my opening and closing parenthesis on my functions, syntax errors on my "<" in my header cpp file, and errors that I'm missing parenthesis.
My first stack is not recognized (main driver file) and in my StackType.cpp file - original is an "undeclared identifier".
Lastly, the left of Push must have class/struct/union - in my for loop when filling the first stack with the rings.
I apologize for all of these issues in advance. Any help you could give me would be greatly appreciated!
Thank you.
======================Stack Header================================
// File: StackType.h
// Stack template class definition.
// Dynamic array implementation
#ifndef StackType
#define StackType
template <class ItemType>
class StackType
{
private:
int ItemType;
ItemType *myStack; // pointer to dynamic array
int _top, _maxSize; // using underscores to remind that it's private
public:
StackType(int numRings = 50); // Constructor
StackType (const StackType<ItemType>&); // Copy Constructor
// Member Functions
void Push(ItemType); // Push
void Pop(ItemType &); // Pop
void stackTop(ItemType &) const; // retrieve top
bool stackIsEmpty() const; // Test for Empty stack
bool stackIsFull() const; // Test for Full stack
~StackType(); // Destructor
};
#endif
=====================Stack cpp file==================================
#include "StackType.h"
#include "stdafx.h"
#include <iostream>
#include <stdio.h>
// Constructor with argument, size is numRings, limit is 50 (set in .h header)
template <class ItemType>
StackType<ItemType>::StackType()
{
_maxSize = numRings;
_top = -1;
}
// Copy Constructor
template <class ItemType>
StackType<ItemType>::StackType(const StackType<ItemType>& original :
_maxSize(original._maxSize), top(original._top)
{
myStack = new ItemType[_maxSize];
for (int i = 0; i <= top; i++) myStack[i] = original.myStack[i];
}
// Destructor
template <class ItemType>
StackType<ItemType>::~StackType()
{
delete [] myStack;
}
// Push
template <class ItemType>
void StackType<ItemType>::Push(StackType<ItemType> ringVal)
{
if(stackIsFull()) cout << "\t There is not enough available memory = the stack is
full!" << endl;
else myStack[++_top] = ringVal;
}
// Pop
template <class ItemType>
void StackType<ItemType>::Pop(StackType<ItemType> &ringVal)
{
if(stackIsEmpty()) cout << "\t The stack is empty!" << endl;
else ringVal = myStack[_top--];
}
// Retrieve stack top without removing it
template <class ItemType>
void StackType<ItemType>::stackTop(StackType<ItemType> &ringVal) const
{
if(stackIsEmpty()) cout << "The stack is empty!";
else ringVal = myStack[_top];
}
// Test for Empty stack
template <class ItemType>
bool StackType<ItemType>::stackIsEmpty() const
{
return (_top < 0);
}
// Test for Full stack
template <class ItemType>
bool StackType<class ItemType>::stackIsFull() const
{
return (_top >= (_maxSize - 1));
}
// end StackType.cpp
=========================Main Driver file=======================================
#include "StackType.h"
#ifdef _DEBUG
#include "StackType.cpp"
#endif // _DEBUG
#include <stack>
#include "StdAfx.h"
#include <iostream>
using namespace std;
// Global Variable - Counter to display the number of moves.
int count = 0;
class StackType;
// Functions Prototypes
void MoveRings(StackType<ItemType>&, StackType<ItemType>&);
// Function to move the rings
void Pegs(int D,StackType<ItemType>& b,StackType<ItemType>& e, StackType<ItemType>& h);
// This is a recursive function.
void Display (int, StackType <ItemType>& , StackType<ItemType>&, StackType<ItemType>&);
// Function to display the pegs
// Main - Driver File
int main()
{
// create 3 empty stacks
StackType<ItemType> FirstPeg; // Receiving an error that this is not identified
StackType<ItemType> EndPeg;
StackType<ItemType> HelperPeg;
// Number of rings.
int numRings;
cout << "\n\t *********** Rings to Pegs (Towers of Hanoi) ***********\n" << endl;
cout << "\t Please Enter the number of rings you want to play with: ";
// Input number of rings
cin >> numRings;
cout << endl;
while(numRings < 0 || isalpha(numRings)) // To make sure that the user did not
// enter an invalid number
{
cout << " Your entry is invalid. Please use only integers. Please re-
enter: ";
cin >> numRings;
cout << endl;
}
for(int i = 1; i <= numRings; i++)
// Fill the first peg with the number of rings.
{
FirstPeg.Push(i);
}
Pegs(int, StackType<ItemType>&, StackType<ItemType>&, StackType<ItemType>&);
// To call the recursive function that will move the rings
Display (int, StackType<ItemType>&, StackType<ItemType>&, StackType<ItemType>&);
// To call the display function
cin.clear();
cin.ignore('\n');
cin.get();
return 0;
}
// This function will move an ring from first peg to the second peg
void MoveRings(StackType<ItemType>& beg, StackType<ItemType>& theEnd) //End
{
int r; // disk will be removed from one stack and added to the other
beg.Pop(r);//pop from source
theEnd.Push(r);//and move to target
}
// This function displays the moves
void Display(int R, StackType<ItemType>& toBegin , StackType<ItemType>& toEnd,
StackType<ItemType>& toHelp)
{
StackType<int> B;// create temporarily first stack
StackType<int> E;// create temporarily End(End) stack
StackType<int> H;// create temporarily helper stack
for(int i = 1; i <= R; i++)
{
toBegin.Pop(i);//moves the ring from source
B.Push(i);//to the temporarily stack to display it
cout << "Beginning Peg:" << &B << endl;
toEnd.Pop(i);//moves the ring from source
E.Push(i);//to the temporarily stack to display it
cout << " End(Final) Peg: " << &E << endl;
toHelp.Pop(i);//moves the ring from source
H.Push(i);//to the temporarily stack to display it
cout << " Helper Peg:" << &H << endl;
}
}
//-------------------------------------------------------------------
void Pegs(int D,StackType<ItemType>& b,StackType<ItemType>& e,StackType<ItemType>& h)
// This is a recursive function.
{
if (D == 0) // The base
{
return 1;
}
else if(D == 1) // If there is only one ring, move this ring from the
// first peg to the end(final) peg
{
MoveRings(b, e); // moves the ring from the first to the end(final) peg
cout<<" Really? You have entered one ring..." << endl;
cout<<" It moves directly from the first peg to the End peg." << endl;
count++; // increment the number of moves
cout << "There has been " << count << " move. "<< endl;// display the
// number of moves
Display (D, b, e, h);
}
else if (D > 1) // a recursive function in order to move the rings
{
Pegs(D - 1, b, e, h); // to move N-1 rings from the first peg to the
// end(final) peg by using the helper peg
MoveRings(b, e);// to move the last ring to the end(final) peg
count++; // increment the number of steps before displaying
cout << "There has been " << count << " moves. "<< endl;
Pegs(D - 1, b, e, h);
// to move N-1 rings from the helper peg to the end(final) peg with the help of
// first peg
//Display ( D(rings), First Peg, End(Final) Peg, Helper Peg );
}
}
One problem that I can see immediately is that your header file defines StackType to prevent double inclusion, which is also used as a class name. After #define StackType, it ends up being a macro that expands to nothing, so your code looks like class { ... }.
You should use a symbol to prevent double inclusion that isn't used for anything else. The typical thing to use is STACKTYPE_H for a file called StackType.h.
Once you've fixed this, some other problems you're experiencing might go away. Please come back with an update if you're having more problems, and post the exact compiler errors if you do.