Added year directories for advent of code

advent_of_code/2021/d5/main.cpp

@@ -0,0 +1,175 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+string FILE_NAME = "5.txt";
+
+// First task: given line segments, find the number of intersected points
+// So don't count multiple intersections on the same point multiple times
+
+
+struct Point{
+    int x;
+    int y;
+};
+
+using Line_Segment = pair<Point, Point>;
+
+istream &operator>> ( istream &is, char const &c ) {
+    istream::sentry sentry (is);
+    if (sentry) { if ( is.peek() == c ) is.get(); else is.setstate(ios_base::failbit); }
+    return is;
+}
+
+istream &operator>> ( istream &is, char const *s ) {
+    istream::sentry sentry (is);
+    if (sentry) {
+        for ( char c; is && (c = *s) != 0; ++s )
+            if ( c == is.peek() ) is.get(); else is.setstate(ios_base::failbit);
+    }
+    return is;
+}
+
+istream &operator>> (istream &in, Point &p){
+    return in >> p.x >> ',' >> p.y;
+}
+
+ostream &operator<< (ostream &out, Point const &p){
+    return out << p.x << ',' << p.y;
+}
+
+bool operator< (const Point &l, const Point &r){
+    return l.x < r.x || (l.x == r.x &&  l.y < r.y);
+}
+
+istream &operator>> (istream &in, Line_Segment &l){
+    return in >> l.first >> "->" >> l.second;
+}
+
+ostream &operator<< (ostream &out, Line_Segment const &l){
+    return out << l.first << " -> " << l.second;
+}
+
+int main(){
+    ios::sync_with_stdio(0);
+    cin.tie(0);
+
+    ifstream file_stream;
+
+    file_stream.open(FILE_NAME);
+    if(!file_stream.is_open()){
+        cerr << "File " << FILE_NAME << " not found\n";
+        return 0;
+    }
+
+    cin.rdbuf(file_stream.rdbuf());
+
+    vector<Line_Segment> lines;
+    while(cin){
+        Line_Segment l;
+        cin >> l;
+        cin >> ws;
+        lines.push_back(l);
+
+        cin.peek();
+    }
+
+    // for(auto &l : lines){
+    //     cout << l << '\n';
+    // }
+
+    int result = 0;
+    map<Point, int> line_points;
+
+    for(auto const &line : lines){
+        Point p1 = line.first, p2 = line.second;
+
+        if(p1.x == p2.x){
+            if(p1.y > p2.y){
+                swap(p1, p2);
+            }
+
+            for(int i = p1.y; i <= p2.y; ++i){
+                line_points[p1]++;
+                p1.y++;
+            }
+        } else if(p1.y == p2.y){
+            if(p1.x > p2.x){
+                swap(p1, p2);
+            }
+
+            for(int i = p1.x; i <= p2.x; ++i){
+                line_points[p1]++;
+                p1.x++;
+            }
+        }
+    }
+
+    for(auto const &lp : line_points){
+        if(lp.second > 1){
+            result++;
+        }
+    }
+
+    cout << "Result part 1: " << result << endl;
+
+    line_points.clear();
+    result = 0;
+
+    for(auto const &line : lines){
+        Point p1 = line.first, p2 = line.second;
+
+        if(p1.x == p2.x){
+            if(p1.y > p2.y){
+                swap(p1, p2);
+            }
+
+            for(int i = p1.y; i <= p2.y; ++i){
+                line_points[p1]++;
+                p1.y++;
+            }
+        } else if(p1.y == p2.y){
+            if(p1.x > p2.x){
+                swap(p1, p2);
+            }
+
+            for(int i = p1.x; i <= p2.x; ++i){
+                line_points[p1]++;
+                p1.x++;
+            }
+        } else{
+            if(p1.x > p2.x){
+                swap(p1, p2);
+            }
+
+            int dif = p2.x - p1.x;
+
+            if(p1.y > p2.y){
+                for(int i = 0; i <= dif; ++i){
+                    line_points[p1]++;
+                    p1.y--;
+                    p1.x++;
+                }
+            } else{
+                for(int i = 0; i <= dif; ++i){
+                    line_points[p1]++;
+                    p1.y++;
+                    p1.x++;
+                }
+            }
+        }
+    }
+
+    for(auto const &lp : line_points){
+        if(lp.second > 1){
+            result++;
+        }
+    }
+
+    cout << "Result part 2: " << result << endl; 
+
+    file_stream.close();
+    cout << flush;
+
+    return 0;
+}