Day 17, part 2 implemented

Author: aeden

day17/Makefile

@@ -1,2 +1,3 @@
 default:
 	c++ -I../ -o bin/p1 src/p1.cpp ../lib/io.cpp
+	c++ -I../ -o bin/p2 src/p2.cpp ../lib/io.cpp

day17/src/p2.cpp

@@ -0,0 +1,237 @@
+#include <iostream>
+#include <fstream>
+#include <string>
+#include <vector>
+#include "lib/io.h"
+
+#include <sstream>
+
+using namespace std;
+
+class Point {
+  public:
+    double x;
+    double y;
+
+    Point() {
+      x = 0;
+      y = 0;
+    }
+
+    Point(double x, double y) {
+      this->x = x;
+      this->y = y;
+    }
+
+    string to_string() {
+      return std::to_string(int(x)) + ":" + std::to_string(int(y));
+    }
+};
+
+class Velocity {
+  public:
+    int x;
+    int y;
+
+    Velocity() {}
+
+    Velocity(int x, int y) {
+      this->x = x;
+      this->y = y;
+    }
+
+    void parse(string s) {
+      int pos = s.find(",");
+      x = stoi(s.substr(0, pos));
+      y = stoi(s.substr(pos + 1));
+    }
+
+    string to_string() {
+      return std::to_string(x) + "," + std::to_string(y);
+    }
+};
+
+class Probe {
+  public:
+    Point location;
+    Velocity velocity;
+
+    Probe() {
+      this->location = Point();
+      this->velocity = Velocity();
+    }
+
+    void step() {
+      location.x += velocity.x;
+      location.y += velocity.y;
+
+      if (velocity.x > 0) {
+        velocity.x -= 1;
+      } else if (velocity.x < 0) {
+        velocity.x += 1;
+      }
+
+      velocity.y -= 1;
+    }
+
+    string to_string() {
+      stringbuf buffer;
+      ostream os (&buffer); 
+
+      os << location.x << "," << location.y << " (" << velocity.x << "," << velocity.y << ")"; 
+
+      return buffer.str();
+    }
+};
+
+const int TEXT_LENGTH=13;
+
+class Target {
+  public:
+  int x_start;
+  int x_end;
+  int y_start;
+  int y_end;
+
+  void parse(string line) {
+    string xydata = line.substr(TEXT_LENGTH);
+    int pos = xydata.find(", ");
+    string xpart = xydata.substr(2, pos - 2);
+    string ypart = xydata.substr(pos + 4);
+    int xsep = xpart.find("..");
+    x_start = stoi(xpart.substr(0, xsep));
+    x_end = stoi(xpart.substr(xsep + 2));
+
+    int ysep = ypart.find("..");
+    y_start = stoi(ypart.substr(0, ysep));
+    y_end = stoi(ypart.substr(ysep + 2));
+  }
+
+  bool in_bounds(Point p) {
+    bool in_x = p.x >= x_start && p.x <= x_end;
+    bool in_y = p.y >= y_start && p.y <= y_end;
+    return in_x && in_y;
+  }
+
+  bool beyond_bounds(Point p) {
+    return beyond_x(p) || beyond_y(p);
+  }
+
+  bool beyond_x(Point p) {
+    return p.x > x_end;
+  }
+
+  bool beyond_y(Point p) {
+    return p.y < y_start;
+  }
+
+  string to_string() {
+    stringbuf buffer;
+    ostream os (&buffer); 
+
+    os << x_start << ".." << x_end << ", " << y_start << ".." << y_end;
+
+    return buffer.str();
+  }
+};
+
+class Result {
+  public:
+    int max_height = 0;
+    bool hit;
+    bool beyond_x;
+    bool beyond_y;
+
+    bool beyond() {
+      return beyond_x || beyond_y;
+    }
+};
+
+void print_debug_info(Result *r, Probe *p) {
+  if (r->hit) {
+    cout << "Probe hit (maxh=" << r->max_height << "): " << p->to_string() << endl;
+  } else if (r->beyond()) {
+    cout << "Probe went beyond (x:" << r->beyond_x << ",y:" << r->beyond_y << "): " << p->to_string() << endl;
+  }
+
+  cout << "Max height: " << r->max_height << endl;
+
+}
+
+Result fire_probe(Probe *p, Target t) {
+  Result r;
+  do {
+    p->step();
+    if (p->location.y > r.max_height) r.max_height = p->location.y;
+    r.hit = t.in_bounds(p->location);
+    r.beyond_x = t.beyond_x(p->location);
+    r.beyond_y = t.beyond_y(p->location);
+  } while (!r.hit && !r.beyond());
+
+  return r;
+}
+
+int main (int argc, char** argv) {
+  string filename;
+  Velocity initial_velocity;
+  bool use_initial_velocity = false;
+
+  if (argc != 2 && argc != 3) {
+    cout << "Usage: " << argv[0] << " datafile velocity" << endl;
+    return 1;
+  } else {
+    filename = argv[1];
+    if (argc == 3) {
+      use_initial_velocity = true;
+      initial_velocity.parse(argv[2]);
+    }
+  }
+
+  vector<string> data = read_data(filename);
+  cout << "Loaded " << data.size() << " data lines" << endl;
+
+  Target t;
+  t.parse(data[0]);
+  cout << "Target range: " << t.to_string() << endl;
+
+  Probe p;
+  if (use_initial_velocity) {
+    cout << "Fire probe with initial velocity given: " << initial_velocity.to_string() << endl;
+    p.velocity = initial_velocity;
+
+    cout << "Probe:" << p.to_string() << endl;
+
+    Result r = fire_probe(&p, t);
+
+    print_debug_info(&r, &p);
+  } else {
+    cout << "Fire probe until all hits determined" << endl;
+
+    int x = 1;
+    int hit_count = 0;
+    Result r;
+
+    while (x <= t.x_end) {
+      // cout << "X = " << x << endl;
+      int y = t.y_start;
+      do {
+        //cout << "Y = " << y << endl;
+        p.location = Point(0, 0);
+        p.velocity = Velocity(x, y);
+        // cout << "Firing probe with velocity " << p.velocity.to_string() << endl;
+        r = fire_probe(&p, t);
+        if (r.hit) hit_count += 1;
+      
+        y++;
+
+      } while (y <= abs(t.y_start));
+
+      x += 1;
+    } 
+    cout << "Hit count: " << hit_count << endl;
+  }
+
+  cout << "Done" << endl;
+
+  return 0;
+}