tsp/src/Tour.cpp

// This is the .cpp file you will edit and turn in.
// We have provided a skeleton for you,
// but you must finish it as described in the spec.
// Also remove these comments here and add your own.
// TODO: remove this comment header

#include "Tour.h"
#include "Node.h"
#include "Point.h"
#include <iostream>

Tour::Tour() : m_startNode(nullptr) {}

Tour::~Tour() {
    if (m_startNode == nullptr)
        return;

    Node *node = m_startNode;
    if (node->next == m_startNode) {
        delete node;
        return;
    }

    do {
        Node *next = node->next;
        delete node;
        node = next;
    } while (node != m_startNode);
}

void Tour::show() const {
    if (m_startNode == nullptr)
        return;

    Node *node = m_startNode;
    do {
        Point &p = node->point;
        // I'm not using std::endl here to avoid flushing stdout for every
        // iteration.
        std::cout << '(' << p.x << ", " << p.y << ")\n";
        node = node->next;
    } while (node != m_startNode);

    // Finally, flush!
    std::flush(std::cout);
}

void Tour::draw(QGraphicsScene *scene) const {
    if (m_startNode == nullptr)
        return;

    Node *node = m_startNode;
    do {
        node->point.drawTo(node->next->point, scene);
        node = node->next;
    } while (node != m_startNode);
}

int Tour::size() const {
    if (m_startNode == nullptr)
        return 0;

    int count = 0;
    Node *node = m_startNode;
    do {
        count++;
        node = node->next;
    } while (node != m_startNode);

    return count;
}

double Tour::distance() const {
    if (m_startNode == nullptr)
        return 0;

    double totalDistance = 0;
    Node *node = m_startNode;
    do {
        totalDistance += node->point.distanceTo(node->next->point);
        node = node->next;
    } while (node != m_startNode);

    return totalDistance;
}

void Tour::insertNearest(Point p) {
    if (m_startNode == nullptr) {
        m_startNode = new Node(p);
        return;
    }

    Node *nearest = m_startNode;
    double minDistance = INFINITY;

    Node *node = m_startNode;
    do {
        double currentDistance = node->point.distanceTo(p);
        if (currentDistance < minDistance) {
            minDistance = currentDistance;
            nearest = node;
        }
        node = node->next;
    } while (node != m_startNode);

    auto *newNode = new Node(p, nearest->next);
    nearest->next = newNode;
}

void Tour::insertSmallest(Point p) {
    if (m_startNode == nullptr) {
        m_startNode = new Node(p);
        return;
    }

    Node *bestNode = m_startNode;
    double minIncrease = INFINITY;

    Node *node = m_startNode;
    do {
        double increase = node->point.distanceTo(p) +
                          p.distanceTo(node->next->point) -
                          node->point.distanceTo(node->next->point);
        if (increase < minIncrease) {
            minIncrease = increase;
            bestNode = node;
        }
        node = node->next;
    } while (node != m_startNode);

    auto *newNode = new Node(p, bestNode->next);
    bestNode->next = newNode;
}