Day 10

input/10.txt

@@ -0,0 +1,144 @@
+addx 2
+addx 3
+addx 1
+noop
+addx 4
+noop
+noop
+noop
+addx 5
+noop
+addx 1
+addx 4
+addx -2
+addx 3
+addx 5
+addx -1
+addx 5
+addx 3
+addx -2
+addx 4
+noop
+noop
+noop
+addx -27
+addx -5
+addx 2
+addx -7
+addx 3
+addx 7
+addx 5
+addx 2
+addx 5
+noop
+noop
+addx -2
+noop
+addx 3
+addx 2
+addx 5
+addx 2
+addx 3
+noop
+addx 2
+addx -29
+addx 30
+addx -26
+addx -10
+noop
+addx 5
+noop
+addx 18
+addx -13
+noop
+noop
+addx 5
+noop
+noop
+addx 5
+noop
+noop
+noop
+addx 1
+addx 2
+addx 7
+noop
+noop
+addx 3
+noop
+addx 2
+addx 3
+noop
+addx -37
+noop
+addx 16
+addx -12
+addx 29
+addx -16
+addx -10
+addx 5
+addx 2
+addx -11
+addx 11
+addx 3
+addx 5
+addx 2
+addx 2
+addx -1
+addx 2
+addx 5
+addx 2
+noop
+noop
+noop
+addx -37
+noop
+addx 17
+addx -10
+addx -2
+noop
+addx 7
+addx 3
+noop
+addx 2
+addx -10
+addx 22
+addx -9
+addx 5
+addx 2
+addx -5
+addx 6
+addx 2
+addx 5
+addx 2
+addx -28
+addx -7
+noop
+noop
+addx 1
+addx 4
+addx 17
+addx -12
+noop
+noop
+noop
+noop
+addx 5
+addx 6
+noop
+addx -1
+addx -17
+addx 18
+noop
+addx 5
+noop
+noop
+noop
+addx 5
+addx 4
+addx -2
+noop
+noop
+noop
+noop
+noop

src/s10a.d

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+module s10a;
+import util;
+
+void main() {
+    string[] commands = readText("input/10.txt").strip.splitter("\n").array;
+    int x = 1;
+    int sum = 0;
+    ulong cycleCount = 0;
+    size_t commandIdx = 0;
+    while (commandIdx < commands.length) {
+        string command = commands[commandIdx++];
+        checkSignalStrength(cycleCount + 1, x, sum);
+        cycleCount++;
+        if (command.startsWith("addx")) {
+            checkSignalStrength(cycleCount + 1, x, sum);
+            x += command[5..$].to!int;
+            cycleCount++;
+        }
+    }
+    writeln(sum);
+}
+
+void checkSignalStrength(ulong i, int x, ref int sum) {
+    if (i == 20 || i == 60 || i == 100 || i == 140 || i == 180 || i == 220) {
+        int signalStrength = cast(int) i * x;
+        sum += signalStrength;
+        writefln!"During cycle %d, x = %d, signal strength: %d"(i, x, signalStrength);
+    }
+}

src/s10b.d

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+module s10a;
+import util;
+
+void main() {
+    string[] commands = readText("input/10.txt").strip.splitter("\n").array;
+    int x = 1;
+    size_t commandIdx = 0;
+    size_t crtIdx = 0;
+    char[] crtRow;
+    while (commandIdx < commands.length) {
+        string command = commands[commandIdx++];
+        drawCrt(crtIdx, crtRow, x);
+        if (command.startsWith("addx")) {
+            drawCrt(crtIdx, crtRow, x);
+            x += command[5..$].to!int;
+        }
+    }
+}
+
+void drawCrt(ref size_t crtIdx, ref char[] crtRow, int x) {
+    bool lit = x == crtIdx - 1 || x == crtIdx || x == crtIdx + 1;
+    crtRow ~= lit ? '#' : '.';
+    crtIdx++;
+    if (crtIdx > 39) {
+        crtIdx = 0;
+        writeln(crtRow);
+        crtRow.length = 0;
+    }
+}