day05

1 files changed, 100 insertions, 0 deletions

diff --git a/day05/day05.cpp b/day05/day05.cpp
new file mode 100644
index 0000000..895dba0
--- /dev/null
+++ b/day05/day05.cpp
@@ -0,0 +1,100 @@
+#include <iostream>
+#include <fstream>
+#include <string>
+#include <vector>
+#include <map>
+
+#include "../utils.h"
+
+class Line {
+	public:
+	Line (int a, int b, int c, int d) : a(a), b(b), c(c), d(d) { }
+	Line (std::string line) {
+		std::vector<std::string> parts, start, end;
+		split(parts, line, "->");
+		split(start, parts[0], ",");
+		split(end, parts[1], ",");
+		a = std::stoi(start[0]);
+		b = std::stoi(start[1]);
+		c = std::stoi(end[0]);
+		d = std::stoi(end[1]);
+		if (c-a == 0) xdir = 0;
+		else { xdir = (c-a) > 0 ? 1 : -1; }
+		if (d-b == 0) ydir = 0;
+		else { ydir = (d-b) > 0 ? 1 : -1; }
+	}
+	int a, b, c, d, xdir, ydir;
+
+	int length () { return abs(a-c) + abs(b-d); }
+
+	bool operator==(Line& oth) {
+		return a == oth.a && b == oth.b && c == oth.c && d == oth.d;
+	}
+};
+
+int main (int argc, char *argv[]) {
+	std::string raw;
+	std::getline(std::ifstream(argv[1]), raw, '\0');
+
+	std::vector<Line> lines;
+	std::vector<std::string> strlines;
+	split(strlines, raw, "\n");
+	for (auto strline : strlines) {
+		if (strline.size() == 0) continue;
+		Line line { strline };
+		if (line.xdir != 0 && line.ydir != 0 
+				&& std::stoi(argv[2]) == 0) continue;
+		lines.push_back(line);
+	}
+
+	int intersections = 0;
+	std::map<std::pair<int, int>, int> overlaps;
+	for (auto& line : lines) {
+		int dist = 0;
+		bool straight = true;
+		if (line.xdir != 0 && line.ydir != 0) straight = false;
+		for (int i=0; dist<line.length()+1; i++) {
+			std::pair pair { line.a + line.xdir*i, line.b + line.ydir*i };
+			if (overlaps.count(pair) == 0) overlaps[pair] = 1;
+			else {
+				if (overlaps[pair] == 1) intersections += 1;
+				overlaps[pair] += 1;
+			}
+			if (straight) dist ++;
+			else dist += 2;
+		}
+	}
+
+
+	int minx = 200;
+	int maxx = -200;
+	int miny = 200;
+	int maxy = -200;
+	for (auto& line : lines) {
+		minx = std::min(minx, std::min(line.a, line.c));
+		maxx = std::max(maxx, std::max(line.a, line.c));
+		miny = std::min(miny, std::min(line.b, line.d));
+		maxy = std::max(maxy, std::max(line.b, line.d));
+	}
+
+	std::cout << "bounds: " 
+		<< minx << " " << maxx << " "
+		<< miny << " " << maxx << std::endl;
+
+	/* visualizer
+	for (int y=miny; y<maxy+1; y++) {
+		for (int x=minx; x<maxx+1; x++) {
+			int amt = overlaps[std::make_pair(x, y)];
+			if (amt > 9) amt = 9;
+			if (amt > 0) std::cout << amt;
+			else std::cout << ".";
+
+		}
+		std::cout << std::endl;
+	}
+	*/
+
+	std::cout << "intersections: " << intersections << std::endl;
+
+	return 0;
+}