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#include <QApplication>
#include <QGraphicsView>
#include <QGraphicsScene>
#include <fstream>
#include <iostream>
#include <algorithm>
#include <vector>
#include <chrono>
#include <cmath>
#include <unordered_map>
#include "Point.h"
// constants
static const int SCENE_WIDTH = 512;
static const int SCENE_HEIGHT = 512;
void render_points(QGraphicsScene* scene, const vector<Point>& points) {
for(const auto& point : points) {
point.draw(scene);
}
}
void render_line(QGraphicsScene* scene, const Point& p1, const Point& p2) {
p1.lineTo(scene, p2);
}
/*
* Return whether v1 contains v2.
*/
template <typename T>
bool vec_contains_vec(const vector<T>& v1, const vector<T>& v2) {
if (v2.size() == 0) {
// every vector contains the empty vector
return true;
}
int i1 = 0;
int i2 = 0;
while (i1 < v1.size()) {
if (v1[i1] == v2[i2]) {
i2++;
if (i2 == v2.size()) {
return true;
}
} else {
i2 = 0;
}
i1++;
}
return false;
}
/*
* Return whether some vector is contained in some other vector before itself.
*/
template <typename T>
bool contained_in_before(const vector<vector<T>>& outer, int index) {
for (int i = 0; i < index; i++) {
if (vec_contains_vec(outer[i], outer[index])) {
return true;
}
}
return false;
}
int main(int argc, char *argv[]) {
QApplication a(argc, argv);
// open file
string filename = "grid6x6.txt";
ifstream input;
input.open(filename);
// the vector of points
vector<Point> points;
// read points from file
int N;
int x;
int y;
input >> N;
for (int i = 0; i < N; ++i) {
input >> x >> y;
points.push_back(Point(x, y));
}
input.close();
// setup graphical window
QGraphicsView *view = new QGraphicsView();
QGraphicsScene *scene = new QGraphicsScene(0, 0, SCENE_WIDTH, SCENE_HEIGHT);
view->setScene(scene);
// draw points to screen all at once
render_points(scene, points);
view->scale(1, -1); //screen y-axis is inverted
view->resize(view->sizeHint());
view->setWindowTitle("Fast Pattern Recognition");
sort(points.begin(), points.end());
auto begin = chrono::high_resolution_clock::now();
// these contain indexes since points can't be compared
// find the corresponding point with points.at(int)
vector<vector<int>> lines;
vector<pair<double, int>> angles;
for (int p1 = 0; p1 < N-1; p1++) {
angles.clear();
for (int p2 = p1 + 1; p2 < N; p2++) {
double angle = points.at(p1).slopeTo(points.at(p2));
angles.push_back({ angle, p2 });
}
sort(angles.begin(), angles.end());
vector<int> line = { p1, 1 };
for (int i = 2; i < angles.size(); i++) {
double prev_angle = angles[i - 1].first;
if (angles[i].first == prev_angle) {
// start of potential line
line.push_back(angles[i].second);
} else {
// end of potential line
if (line.size() >= 4) {
lines.push_back(line);
}
line.clear();
line.push_back(p1);
line.push_back(angles[i].second);
}
}
if (line.size() >= 4) {
lines.push_back(line);
}
}
for (int i = 0; i < lines.size();) {
if (contained_in_before(lines, i)) {
lines.erase(lines.begin() + i); //NOTE should check before inserting instead
} else {
i++;
}
}
for (const auto& line : lines) {
render_line(scene, points.at(line.front()), points.at(line.back()));
}
cout << lines.size() << " draws" << endl;
auto end = chrono::high_resolution_clock::now();
cout << "Computing line segments took "
<< std::chrono::duration_cast<chrono::milliseconds>(end - begin).count()
<< " milliseconds." << endl;
///////////
// tests //
///////////
vector<int> v1 = {1, 2, 3};
vector<int> v2 = {2, 3};
vector<int> v3 = {3};
vector<int> v4 = {2, 3, 4};
cout << vec_contains_vec(v1, v2) << " " // expect true
<< vec_contains_vec(v2, v1) << " " // expect false
<< vec_contains_vec(v1, v3) << " " // expect true
<< vec_contains_vec(v1, v4) << endl; // expect false
vector<vector<int>> outer = {{1,2,3}, {2,3}, {3,4}};
cout << contained_in_before(outer, 0) << " " // expect false
<< contained_in_before(outer, 1) << " " // expect true
<< contained_in_before(outer, 2) << endl; // expect false
view->show();
return a.exec(); // start Qt event loop
}
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