Day 2.2

02/src/main.zig

@@ -11,4 +11,34 @@ pub fn main() anyerror!void {
 
     // Part 1
     std.debug.warn("Part 1: {}\n", try intcode.runCopy(alloc, program, 12, 2));
+
+    // Part 2: 100*100 = 10,000 combinations to try.
+    var memory: []u32 = try alloc.alloc(u32, program.len);
+    var done: bool = false;
+    var noun: u32 = 0;
+    var verb: u32 = 0;
+
+    std.debug.warn("Part 2: Searching...");
+    while (!done) {
+        std.mem.copy(u32, memory, program);
+        const result = try intcode.run(memory, noun, verb);
+
+        // Too high: 250800 (noun=33, verb=76)
+        if (result == 19690720) {
+            std.debug.warn("OK! noun={} verb={}\n", noun, verb);
+            done = true;
+        }
+
+        noun += 1;
+        if (noun > 100) {
+            noun = 0;
+            verb += 1;
+
+            if (verb > 100) {
+                std.debug.warn("failed!\n");
+            } else {
+                std.debug.warn(".");
+            }
+        }
+    }
 }

lib/intcode/intcode.zig

@@ -47,7 +47,7 @@ pub fn run(program: []u32, noun: u32, verb: u32) anyerror!u32 {
     // TODO: create a nice struct
 
     while (!exit) {
-        std.debug.warn(" IP {d:4}: ", ip);
+        //        std.debug.warn(" IP {d:4}: ", ip);
         const opcode = switch (program[ip]) {
             1 => {
                 var a = program[program[ip + 1]];
@@ -55,7 +55,7 @@ pub fn run(program: []u32, noun: u32, verb: u32) anyerror!u32 {
                 var dest = program[ip + 3];
                 var result = a + b;
 
-                std.debug.warn("ADD:  [{}] + [{}] => {} : {} + {} = {} => {}\n", ip + 1, ip + 2, dest, a, b, result, dest);
+                //                std.debug.warn("ADD:  [{}] + [{}] => {} : {} + {} = {} => {}\n", ip + 1, ip + 2, dest, a, b, result, dest);
                 program[dest] = result;
                 ip += 4;
             },
@@ -65,12 +65,12 @@ pub fn run(program: []u32, noun: u32, verb: u32) anyerror!u32 {
                 var dest = program[ip + 3];
                 var result = a * b;
 
-                std.debug.warn("MULT: [{}] + [{}] => {} : {} + {} = {} => {}\n", ip + 1, ip + 2, dest, a, b, result, dest);
+                //                std.debug.warn("MULT: [{}] + [{}] => {} : {} + {} = {} => {}\n", ip + 1, ip + 2, dest, a, b, result, dest);
                 program[dest] = result;
                 ip += 4;
             },
             99 => {
-                std.debug.warn("EXIT\n");
+                //                std.debug.warn("EXIT\n");
                 exit = true;
             },
             else => {