Day 17

2024/17/index.ts

@@ -4,64 +4,66 @@ const input = fs.readFileSync(__dirname + '/input.txt', 'utf8');
 
 const lines = input.split("\n");
 
-let registerA = parseInt(lines[0].split(' ')[2]);
+let registerA = BigInt(parseInt(lines[0].split(' ')[2]));
-let registerB = parseInt(lines[1].split(' ')[2]);
+let registerB = BigInt(parseInt(lines[1].split(' ')[2]));
-let registerC = parseInt(lines[2].split(' ')[2]);
+let registerC = BigInt(parseInt(lines[2].split(' ')[2]));
 
-let output: Array<number> = [];
+let output: Array<string> = [];
 
-const instructions = lines[4].split(' ')[1].split(',').map((i: string) => parseInt(i));
+let instructionsStr = lines[4].split(' ')[1];
+const instructions = instructionsStr.split(',').map((i: string) => parseInt(i));
 
 let pointer = 0;
 
-function combo(op: number): number {
+function combo(op: bigint): bigint {
-    if (op <= 3) {
+    if (op <= 3n) {
         return op;
     }
-    if (op === 4) {
+    if (op === 4n) {
         return registerA;
     }
-    if (op === 5) {
+    if (op === 5n) {
         return registerB;
     }
-    if (op === 6) {
+    if (op === 6n) {
         return registerC;
     }
     return op;
 }
 
 function call(ins: number, op: number) {
+    let bop = BigInt(op);
     if (ins === 0) {
-        op = combo(op);
+        bop = combo(bop);
-        registerA = Math.round(registerA / (2 ** op));
+        registerA = registerA >> bop;
         return;
     }
     if (ins === 1) {
-        registerB = registerB ^ op;
+        registerB ^= bop;
         return;
     }
     if (ins === 2) {
-        op = combo(op);
+        bop = combo(bop);
-        registerB = op % 8;
+        registerB = bop & 7n;
         return;
     }
     if (ins === 4) {
-        registerB = registerB ^ registerC;
+        registerB ^= registerC;
         return;
     }
     if (ins === 5) {
-        op = combo(op);
+        bop = combo(bop);
-        output.push(op % 8);
+        output.push(''+(bop & 7n));
         return;
     }
     if (ins === 6) {
-        op = combo(op);
+        bop = combo(bop);
-        registerB = Math.round(registerA / (2 ** op));
+        registerB = registerA >> bop;
         return;
     }
     if (ins === 7) {
-        op = combo(op);
+        bop = combo(bop);
-        registerC = Math.round(registerA / (2 ** op));
+        registerC = registerA >> bop;
         return;
     }
 }
@@ -76,24 +78,23 @@ ins: ${typeof instructions[pointer] !== 'undefined' ? instructions[pointer] : 'N
 op: ${typeof instructions[pointer+1] !== 'undefined' ? instructions[pointer+1] : 'NA'}
 combo: ${typeof instructions[pointer+1] !== 'undefined' ? combo(instructions[pointer+1]) : 'NA'}
 
-Output: ${output.join(',')}
+Output: ${output}
 `);
 }
 
 function run() {
     while (pointer < instructions.length) {
-        printPC();
         const ins = instructions[pointer];
         const op = instructions[pointer + 1];
 
         if (ins === 3) {
-            pointer = registerA === 0 ? pointer + 2 : op;
+            pointer = registerA === 0n ? pointer + 2 : op;
         } else {
             call(ins, op);
             pointer += 2;
         }
     }
-    printPC();
 }
 
 run();
+console.log(output.join(','));

2024/17/index2.ts

@@ -0,0 +1,42 @@
+const fs = require('fs');
+
+const input = fs.readFileSync(__dirname + '/input.txt', 'utf8');
+
+const lines = input.split("\n");
+
+let instructionsStr = lines[4].split(' ')[1];
+const instructions = instructionsStr.split(',').map((i: string) => parseInt(i));
+
+function run(a: bigint) {
+    return (((a & 7n) ^ 7n) ^ (a >> ((a & 7n) ^ 3n))) & 7n;
+}
+
+let regA = 0n;
+
+for (let i = instructions.length - 1; i >= 0; i--) {
+    for (let a = 0n; a < 8n; a++) {
+        const testA = (regA << 3n) + a;
+        const out = run(testA);
+        if (out === BigInt(instructions[i])) {
+            regA = testA;
+            break;
+        }
+    }
+}
+console.log(regA);
+
+/*
+b = a % 8;
+b = b ^ 3;
+c = a / (2 ** b)
+a = a / 4
+b = b ^ 4
+b = b ^ c
+
+x = (((a & 7) ^ 7) ^ (a / (2 ** ((a & 7) ^ 3)))) & 7
+*/
+
+/*
+a = a >> 3
+x = a & 7
+*/