day 13

Makefile

@@ -118,6 +118,16 @@ day12part2:
 	@echo
 	./build/day12part2
 
+day13part1:
+	fpc src/day13/part1.pas -obuild/day13part1
+	@echo
+	./build/day13part1
+
+day13part2:
+	fpc src/day13/part2.pas -obuild/day13part2
+	@echo
+	./build/day13part2
+
 
 clean:
 	rm build/*

src/day13/part1.pas

@@ -0,0 +1,142 @@
+{$mode objfpc}
+{$RANGECHECKS ON}
+
+program day12part1;
+uses sysutils;
+
+type
+    Tmap = record
+        map: array[1..100] of string;
+        height: int32;
+        width: int32;
+    end;
+
+function max(a, b: int32): int32;
+begin
+    max := a;
+    if b > a then
+        max := b;
+end;
+
+{ check for mirrors that lay vertically (column mirror) }
+function check_v_mirror(map: Tmap; col: int32): boolean;
+var
+    i, j: int32;
+begin
+
+    check_v_mirror := true;
+    for j := 1 to map.height do 
+    begin
+        for i := max(1, 2 * col - map.width + 1) to col do
+        begin
+            // writeln(i, ' ',  col*2 - i);
+            if map.map[j, i] <> map.map[j, col * 2 - i + 1] then
+            begin
+                check_v_mirror := false;
+                break
+            end;
+        end;
+
+        if not check_v_mirror then
+            break;
+    end;
+
+    check_v_mirror := check_v_mirror;
+
+end;
+
+{ check for mirrors that lay vertically (column mirror) }
+function check_h_mirror(map: Tmap; row: int32): boolean;
+var
+    i, j: int32;
+begin
+
+    check_h_mirror := true;
+    for j := 1 to map.width do 
+    begin
+        for i := max(1, 2 * row - map.height + 1) to row do
+        begin
+            //writeln(i, ' ',  row*2 - i + 1);
+            if map.map[i, j] <> map.map[row * 2 - i + 1, j] then
+            begin
+                check_h_mirror := false;
+                break
+            end;
+        end;
+
+        if not check_h_mirror then
+            break;
+    end;
+end;
+
+
+function get_mirror(map: Tmap): int32;
+var
+    i: int32;
+begin
+    { check vertical ones first } 
+    for i := 1 to map.width - 1 do
+    begin
+        if check_v_mirror(map, i) then
+        begin
+            get_mirror := i;
+            exit;
+        end;
+    end;
+
+    { check horizontal ones now }
+    for i := 1 to map.height - 1 do
+    begin
+        if check_h_mirror(map, i) then
+        begin
+            get_mirror := i shl 6 + i shl 5 + i shl 2;
+            exit;
+        end;
+    end;
+
+end;
+
+var
+
+    map: Tmap;
+    file_: text;
+    s: string;
+    total, map_count: int32;
+
+begin
+
+    assign(file_, 'resources/day13.txt');
+    reset(file_);
+
+    total := 0;
+    map_count := 0;
+
+    while not EOF(file_) do
+    begin
+
+        readln(file_, s);
+        writeln(s);
+        if length(s) = 0 then
+        begin
+            // come back to this
+
+            total := total + get_mirror(map);
+
+            map_count := 0;
+
+        end
+        else
+        begin
+
+            map_count := map_count + 1;
+            map.map[map_count] := s;
+            map.height := map_count;
+            map.width := length(s);
+
+        end;
+
+    end;
+
+    writeln(total);
+
+end.

src/day13/part2.pas

@@ -0,0 +1,149 @@
+{$mode objfpc}
+{$RANGECHECKS ON}
+
+program day12part1;
+uses sysutils;
+
+type
+    Tmap = record
+        map: array[1..100] of string;
+        height: int32;
+        width: int32;
+    end;
+
+function max(a, b: int32): int32;
+begin
+    max := a;
+    if b > a then
+        max := b;
+end;
+
+{ check for mirrors that lay vertically (column mirror) }
+function check_v_mirror(map: Tmap; col: int32): boolean;
+var
+    i, j: int32;
+    errors: int32;
+begin
+
+    errors := 0;
+    for j := 1 to map.height do 
+    begin
+        for i := max(1, 2 * col - map.width + 1) to col do
+        begin
+            // writeln(i, ' ',  col*2 - i);
+            if map.map[j, i] <> map.map[j, col * 2 - i + 1] then
+            begin
+                errors := errors + 1;
+                if errors > 1 then
+                    break;
+            end;
+        end;
+
+        if errors > 1 then
+            break;
+    end;
+
+    check_v_mirror := errors = 1;
+
+end;
+
+{ check for mirrors that lay vertically (column mirror) }
+function check_h_mirror(map: Tmap; row: int32): boolean;
+var
+    i, j: int32;
+    errors: int32;
+begin
+
+    errors := 0;
+    for j := 1 to map.width do 
+    begin
+        for i := max(1, 2 * row - map.height + 1) to row do
+        begin
+            //writeln(i, ' ',  row*2 - i + 1);
+            if map.map[i, j] <> map.map[row * 2 - i + 1, j] then
+            begin
+                errors := errors + 1;
+                if errors > 1 then
+                    break;
+            end;
+        end;
+
+        if errors > 1 then
+            break;
+    end;
+
+    check_h_mirror := errors = 1;
+end;
+
+
+function get_mirror(map: Tmap): int32;
+var
+    i: int32;
+begin
+    { check vertical ones first } 
+    for i := 1 to map.width - 1 do
+    begin
+        if check_v_mirror(map, i) then
+        begin
+            get_mirror := i;
+            exit;
+        end;
+    end;
+
+    { check horizontal ones now }
+    for i := 1 to map.height - 1 do
+    begin
+        if check_h_mirror(map, i) then
+        begin
+            get_mirror := i shl 6 + i shl 5 + i shl 2;
+            exit;
+        end;
+    end;
+
+    if get_mirror = 0 then
+        writeln('oh fuck');
+
+end;
+
+var
+
+    map: Tmap;
+    file_: text;
+    s: string;
+    total, map_count: int32;
+
+begin
+
+    assign(file_, 'resources/day13.txt');
+    reset(file_);
+
+    total := 0;
+    map_count := 0;
+
+    while not EOF(file_) do
+    begin
+
+        readln(file_, s);
+        if length(s) = 0 then
+        begin
+
+            total := total + get_mirror(map);
+
+            map_count := 0;
+
+        end
+        else
+        begin
+
+            map_count := map_count + 1;
+            map.map[map_count] := s;
+            map.height := map_count;
+            map.width := length(s);
+
+        end;
+
+    end;
+
+    writeln(total);
+
+end.