day11

3 files changed, 73 insertions, 15 deletions

diff --git a/day11/example.txt b/day11/example.txt
new file mode 100644
index 0000000..986aad4
--- /dev/null
+++ b/day11/example.txt
@@ -0,0 +1,10 @@
+...#......
+.......#..
+#.........
+..........
+......#...
+.#........
+.........#
+..........
+.......#..
+#...#.....
diff --git a/day11/solution.zig b/day11/solution.zig
index 059a120..e9ddfed 100644
--- a/day11/solution.zig
+++ b/day11/solution.zig
@@ -9,15 +9,68 @@ const fin = mem.trim(u8, @embedFile("./input.txt"), &std.ascii.whitespace);
 var gpa = std.heap.GeneralPurposeAllocator(.{}){};
 const allocator = gpa.allocator();
 
-pub fn part1() void {
-    // Part 1 goes here
-}
+const u64HashMap = HashMap(u64, void, u64ctx, 80);
+const u64ctx = struct {
+    pub fn hash(_: @This(), k: u64) u64 {
+        return k;
+    }
+
+    pub fn eql(_: @This(), lhs: u64, rhs: u64) bool {
+        return lhs == rhs;
+    }
+};
+
+pub fn solve(galaxies: [][2]usize, popRows: u64HashMap, popCols: u64HashMap) !void {
+    var nEmpty: usize = 0;
+    var sDist: usize = 0;
+
+    for (galaxies[0..], 0..) |this, i| {
+        for (galaxies[i + 1 ..]) |other| {
+            const ai = @min(this[0], other[0]);
+            const aj = @min(this[1], other[1]);
+            const bi = @max(this[0], other[0]);
+            const bj = @max(this[1], other[1]);
+
+            sDist += bi - ai + bj - aj;
 
-pub fn part2() void {
-    // Part 2 goes here
+            for (ai..bi) |row| {
+                if (popRows.get(row) == null) {
+                    nEmpty += 1;
+                }
+            }
+
+            for (aj..bj) |col| {
+                if (popCols.get(col) == null) {
+                    nEmpty += 1;
+                }
+            }
+        }
+    }
+
+    const part1 = sDist + nEmpty;
+    const part2 = sDist + nEmpty * 999_999;
+
+    print("{d}\n", .{part1});
+    print("{d}\n", .{part2});
 }
 
 pub fn main() !void {
-    part1();
-    part2();
+    var splitLines = mem.splitScalar(u8, fin, '\n');
+    var galaxies = ArrayList([2]usize).init(allocator);
+    var popRows = u64HashMap.init(allocator);
+    var popCols = u64HashMap.init(allocator);
+    defer galaxies.deinit();
+
+    var i: usize = 0;
+    while (splitLines.next()) |row| : (i += 1) {
+        for (row, 0..) |c, j| {
+            if (c == '#') {
+                try popRows.put(i, {});
+                try popCols.put(j, {});
+                try galaxies.append(.{ i, j });
+            }
+        }
+    }
+
+    try solve(galaxies.items, popRows, popCols);
 }
diff --git a/template.zig b/template.zig
index 059a120..c9ec529 100644
--- a/template.zig
+++ b/template.zig
@@ -9,15 +9,10 @@ const fin = mem.trim(u8, @embedFile("./input.txt"), &std.ascii.whitespace);
 var gpa = std.heap.GeneralPurposeAllocator(.{}){};
 const allocator = gpa.allocator();
 
-pub fn part1() void {
-    // Part 1 goes here
-}
-
-pub fn part2() void {
-    // Part 2 goes here
+pub fn solve() void {
+    // solve
 }
 
 pub fn main() !void {
-    part1();
-    part2();
+    solve();
 }