diff --git a/day8/input b/day8/input
new file mode 100644
index 0000000..62e61dd
--- /dev/null
+++ b/day8/input
@@ -0,0 +1,634 @@
+acc +15
+acc +2
+acc -14
+jmp +362
+acc +22
+nop +236
+jmp +474
+acc +10
+jmp +1
+acc +0
+jmp +236
+acc +10
+acc +14
+jmp +334
+acc +12
+acc -1
+jmp +478
+jmp +90
+jmp +208
+acc +49
+jmp +94
+acc +2
+acc -8
+jmp +375
+nop +21
+acc +0
+acc +10
+nop +25
+jmp +492
+nop +182
+acc +49
+acc -12
+jmp -14
+acc -16
+jmp +140
+acc -3
+acc -18
+acc +28
+acc -6
+jmp +558
+acc +2
+acc +27
+nop +438
+acc +41
+jmp +508
+acc +13
+jmp +117
+acc +21
+acc -13
+acc +34
+jmp +1
+jmp +1
+nop +451
+acc +28
+acc +31
+acc +31
+jmp +280
+acc +32
+acc +35
+acc -18
+jmp +509
+acc -15
+acc -8
+nop +288
+acc -16
+jmp +376
+acc -19
+acc -8
+acc +11
+acc +10
+jmp +50
+acc +19
+nop -58
+acc -9
+jmp +43
+acc +10
+acc +2
+nop -63
+jmp +280
+acc -7
+jmp +175
+jmp +69
+acc +16
+acc +9
+acc -2
+acc -5
+jmp +276
+nop +195
+acc +50
+acc -8
+jmp -55
+nop +1
+nop -78
+acc +31
+jmp +535
+acc +9
+acc +33
+acc +4
+acc +48
+jmp +8
+acc +30
+acc +42
+acc +18
+acc +37
+jmp -69
+nop +121
+jmp +44
+acc +3
+acc +33
+acc -6
+acc +37
+jmp +403
+acc -6
+jmp +245
+jmp -93
+acc +5
+jmp +406
+jmp -26
+nop -47
+jmp +239
+acc +7
+acc +31
+acc +14
+acc +0
+jmp +291
+acc +46
+jmp +394
+acc +44
+acc +36
+nop +45
+jmp +137
+acc -16
+acc +10
+acc -4
+acc +7
+jmp +76
+acc +24
+jmp +93
+acc +17
+acc +0
+acc +6
+acc +4
+jmp +385
+acc -8
+acc +49
+acc +28
+jmp +95
+nop +12
+acc +33
+jmp +153
+nop +254
+acc +18
+acc -16
+acc +50
+jmp +299
+acc +27
+acc +47
+acc -17
+jmp -15
+acc +35
+acc +14
+jmp +204
+jmp +93
+acc +46
+nop -5
+nop -158
+jmp +221
+jmp +321
+acc -2
+acc +49
+acc +3
+acc -17
+jmp -52
+jmp +7
+nop +52
+acc +25
+jmp +376
+acc -3
+nop -133
+jmp +32
+jmp +328
+nop +374
+acc +37
+acc +6
+jmp +92
+acc +47
+nop +394
+jmp -13
+jmp -170
+acc +9
+jmp -47
+acc -18
+acc +27
+jmp +1
+acc +3
+acc -5
+jmp +337
+acc +21
+jmp +364
+acc +24
+acc +43
+acc +50
+jmp +58
+jmp -18
+acc +30
+jmp +144
+nop +5
+acc +50
+nop +245
+nop +133
+jmp +270
+jmp -22
+nop -76
+jmp +398
+acc +40
+acc +30
+jmp +361
+acc +36
+acc +30
+jmp +392
+acc -17
+nop +71
+acc -12
+jmp +102
+acc +17
+jmp +283
+acc -16
+jmp +65
+nop -2
+jmp +149
+jmp -103
+jmp -179
+acc +46
+jmp +289
+acc +48
+jmp +114
+acc +13
+jmp +114
+nop +215
+nop -89
+jmp +337
+acc -2
+acc +2
+acc -7
+jmp -18
+jmp -51
+acc +30
+acc +43
+acc +28
+jmp -188
+acc +36
+acc +7
+acc -5
+acc +38
+jmp +88
+jmp +225
+acc -14
+acc -3
+acc -15
+jmp +66
+acc +7
+acc +43
+nop -210
+acc -9
+jmp +109
+acc -10
+jmp +242
+acc -5
+acc +15
+acc +8
+jmp +310
+acc +31
+acc -2
+acc +11
+acc -15
+jmp +103
+acc +32
+jmp -92
+acc -10
+acc +6
+acc -1
+jmp -131
+acc +43
+acc +30
+acc +13
+acc +33
+jmp +25
+acc +9
+acc -14
+acc +19
+acc +44
+jmp -50
+acc -8
+acc +9
+jmp +312
+jmp -96
+acc -3
+acc -3
+acc +24
+jmp +94
+acc -15
+jmp +61
+acc +19
+nop -89
+acc +24
+nop -94
+jmp +5
+acc -13
+acc +25
+acc +42
+jmp +1
+jmp +137
+acc +44
+acc +44
+acc +41
+jmp +152
+jmp +144
+acc -1
+nop +293
+jmp -120
+acc -17
+nop -171
+acc +27
+jmp -173
+jmp +231
+acc +3
+jmp +109
+acc +18
+acc +32
+acc -14
+acc -8
+jmp +177
+acc +28
+jmp -134
+nop +277
+jmp -124
+jmp +167
+nop +274
+acc +6
+acc +43
+acc +10
+jmp -320
+acc +28
+acc -9
+acc +22
+jmp -90
+jmp -203
+jmp -133
+jmp -6
+jmp -181
+jmp +170
+acc +40
+acc +5
+jmp -274
+acc +36
+acc +24
+nop +6
+jmp -339
+jmp -251
+acc +10
+acc +10
+jmp -347
+jmp +263
+acc +37
+jmp -201
+acc -11
+acc +42
+jmp +153
+nop -179
+acc -9
+jmp +8
+jmp -289
+jmp -25
+acc +45
+jmp -142
+acc +42
+acc -10
+jmp +83
+acc +43
+acc +3
+acc -6
+jmp -222
+acc +41
+acc +14
+acc +7
+acc +2
+jmp -35
+jmp +168
+acc +11
+acc +18
+acc +8
+acc -4
+jmp -203
+acc +44
+jmp +10
+nop -184
+acc +0
+jmp +91
+acc -5
+nop +226
+acc +46
+acc -10
+jmp -15
+jmp -321
+acc +0
+acc +33
+jmp +82
+jmp +1
+acc -12
+acc +30
+jmp +152
+acc +6
+jmp -208
+acc +43
+jmp +39
+acc +23
+acc +23
+acc +24
+acc +26
+jmp -390
+acc +15
+acc +3
+acc +14
+acc +46
+jmp -239
+acc -10
+acc +19
+jmp +167
+acc +46
+acc +0
+jmp -280
+acc -7
+jmp -107
+acc +13
+jmp -76
+acc +48
+jmp -65
+nop +23
+nop -89
+acc +47
+jmp -304
+acc -5
+jmp +1
+acc +50
+acc +37
+jmp -129
+acc +27
+jmp +1
+jmp -212
+acc +18
+acc +29
+acc +1
+jmp -74
+acc +24
+acc -12
+jmp -173
+acc -18
+acc -6
+nop -156
+jmp -309
+acc +46
+acc -13
+acc +41
+acc +11
+jmp -188
+acc +32
+jmp -190
+acc +31
+acc +30
+jmp -122
+acc -7
+jmp +37
+acc +2
+acc +16
+acc +45
+acc +44
+jmp -376
+acc +47
+jmp +1
+jmp -147
+acc +47
+acc -18
+acc -1
+acc +2
+jmp -152
+acc +12
+acc -8
+jmp +90
+nop +67
+acc +9
+jmp +1
+jmp -377
+jmp +1
+jmp -238
+jmp +1
+acc +47
+acc +7
+acc +31
+jmp -427
+acc +10
+acc +13
+nop +13
+jmp -8
+nop -292
+acc +11
+nop -203
+jmp -164
+jmp -19
+acc +31
+jmp -289
+acc -7
+acc -16
+acc +35
+jmp -333
+jmp -500
+acc +32
+acc +29
+acc +18
+acc +14
+jmp -161
+jmp -60
+jmp +6
+acc +4
+nop -108
+acc +27
+jmp +2
+jmp -133
+acc +2
+jmp -103
+acc +40
+nop -512
+acc +48
+jmp -196
+acc +47
+acc +40
+nop -346
+acc -2
+jmp -530
+acc +17
+nop -31
+acc +1
+jmp -74
+acc -15
+acc +4
+nop -330
+acc +32
+jmp -115
+acc -3
+jmp +1
+acc +14
+acc +31
+jmp -352
+jmp -10
+acc +18
+jmp -322
+acc +41
+jmp +59
+acc -16
+nop -359
+acc +29
+acc +26
+jmp -418
+acc +10
+acc +47
+jmp -519
+acc -5
+nop +40
+acc +30
+jmp -195
+acc +31
+acc +3
+acc +8
+jmp -10
+acc -12
+acc +21
+acc -1
+jmp +30
+jmp -341
+acc -5
+jmp -405
+acc -13
+jmp -170
+acc +24
+acc -16
+acc +20
+acc +17
+jmp -145
+acc +42
+acc +33
+jmp -395
+nop -142
+acc +45
+acc +15
+jmp -399
+nop -223
+jmp -299
+jmp -453
+acc -6
+nop -498
+acc +42
+jmp -112
+acc +39
+acc +46
+acc +4
+acc +27
+jmp -234
+jmp +1
+acc +45
+acc +47
+jmp -307
+jmp -378
+jmp -431
+acc +13
+acc +29
+jmp -282
+acc +4
+acc -3
+acc +37
+acc +40
+jmp -32
+nop -148
+acc +38
+acc +40
+acc +18
+jmp -171
+nop -546
+jmp -490
+acc +36
+jmp -514
+acc +27
+acc -10
+nop -560
+acc +44
+jmp +1
diff --git a/day8/src/main.zig b/day8/src/main.zig
index d29869f..13f71e4 100644
--- a/day8/src/main.zig
+++ b/day8/src/main.zig
@@ -1,5 +1,222 @@
 const std = @import("std");
 
 pub fn main() anyerror!void {
-    std.log.info("All your codebase are belong to us.", .{});
+    var arena = std.heap.ArenaAllocator.init(std.heap.page_allocator);
+    defer arena.deinit();
+    var gpa = &arena.allocator;
+
+    var program = try Program.init(gpa);
+    defer program.*.deinit();
+
+    var f = try std.fs.cwd().openFile("input", .{});
+    var contents = try f.readToEndAlloc(gpa, std.math.maxInt(u32));
+    var it = std.mem.tokenize(contents, "\n");
+    while (it.next()) |line| {
+        var s = try Statement.from_string(line);
+        try program.code.append(s);
+    }
+    std.log.debug("Loaded program with {} statements", .{program.code.items.len});
+    _ = try program.run();
+
+    // Part 2
+    // Exactly one nop should be a jmp or a jmp a noop
+    var i : usize = 0;
+    while (i < program.code.items.len) : (i += 1) {
+        if (program.code.items[i].op == .acc) {
+            continue;
+        }
+        // Mutate
+        program.code.items[i].op = switch(program.code.items[i].op) {
+            .acc => Operation.acc,
+            .jmp => Operation.nop,
+            .nop => Operation.jmp,
+        };
+        // Test
+        var run_ok = program.run() catch false;
+        // Undo mutation
+        program.code.items[i].op = switch(program.code.items[i].op) {
+            .acc => Operation.acc,
+            .jmp => Operation.nop,
+            .nop => Operation.jmp,
+        };
+        if (run_ok) {
+            std.log.info("By changing statement {}, the program exited okay", .{i});
+            break;
+        }
+    }
+}
+
+pub const Operation = enum {
+    nop,
+    acc,
+    jmp
+};
+
+pub const ParseError = error {
+    UnknownStatement,
+};
+
+pub const Statement = struct {
+    op: Operation,
+    arg: i32,
+
+    /// Modifies acc and returns the offset for the next operation
+    pub fn execute(self: *Statement, acc: *i32) i32 {
+        var delta : i32 = switch (self.op) {
+            .nop => 1,
+            .jmp => self.arg,
+            .acc => 1,
+        };
+        if (self.op == .acc) {
+            acc.* += self.arg;
+        }
+        return delta;
+    }
+
+    pub fn from_string(line: []const u8) !Statement {
+        var arg : i32 = 0;
+        var op : Operation = undefined;
+
+        var it = std.mem.tokenize(line, " ");
+        if (it.next()) |l| {
+            if (std.mem.eql(u8, l, "nop")) {
+                op = Operation.nop;
+            }
+            else if (std.mem.eql(u8, l, "acc")) {
+                op = Operation.acc;
+            }
+            else if (std.mem.eql(u8, l, "jmp")) {
+                op = Operation.jmp;
+            }
+            else {
+                std.log.err("Unknown statement: '{}'", .{l});
+                return ParseError.UnknownStatement;
+            }
+        }
+        else {
+            // Error, and operator is required
+            unreachable;
+        }
+        if (it.next()) |l| {
+            arg = atoi(l);
+        }
+        else {
+            // Error, we need an arg
+            unreachable;
+        }
+
+        while(it.next()) |l| {
+            // Error, there shouldn't be anything else on the line
+            unreachable;
+        }
+
+        return Statement {
+            .op = op,
+            .arg = arg,
+        };
+    }
+};
+
+pub const Program = struct {
+    code: std.ArrayList(Statement),
+    allocator: *std.mem.Allocator,
+    accumulator: i32 = 0,
+
+    pub fn init(a: *std.mem.Allocator) !*Program {
+        const self = try a.create(Program);
+        errdefer a.destroy(self);
+
+        self.* = Program {
+            .code = std.ArrayList(Statement).init(a),
+            .allocator = a,
+        };
+        return self;
+    }
+
+    pub fn deinit(self: *Program) void {
+        self.code.deinit();
+        self.allocator.destroy(self);
+    }
+
+    pub fn run(self: *Program) !bool {
+        self.accumulator = 0;
+        var next_statement_index : usize = 0;
+        // Statement counter
+        var map = std.hash_map.AutoHashMap(usize, u32).init(self.allocator);
+        defer map.deinit();
+
+        var ended_ok = false;
+        while (true) {
+            // Check if we have already exectured this index
+            var n_accumulator : i32 = self.accumulator;
+            if (map.contains(next_statement_index)) {
+                std.log.warn("Infinite loop detected. Statement {} would have run twice",
+                             .{next_statement_index});
+                std.log.warn("Acc value at break: {}", .{self.accumulator});
+                break;
+            }
+            else {
+                try map.put(next_statement_index, 1);
+            }
+
+            var delta = self.code.items[next_statement_index].execute(&n_accumulator);
+            //std.log.debug("Before {}, After {} [statement {} new offset {}] {}",
+            //              .{self.accumulator, n_accumulator, next_statement_index,
+            //                delta, self.code.items[next_statement_index]});
+            if (delta < 0) {
+                next_statement_index -= @intCast(usize, try std.math.absInt(delta));
+            }
+            else {
+                next_statement_index += @intCast(usize, delta);
+            }
+            std.debug.assert(next_statement_index >= 0);
+            if (next_statement_index >= self.code.items.len) {
+                std.log.warn("Reached end of code, or jumping past end ({}, {} statements).",
+                             .{next_statement_index, self.code.items.len});
+                std.log.warn("Acc value at end: {}", .{self.accumulator});
+                ended_ok = true; // maybe...
+                break;
+            }
+            self.accumulator = n_accumulator;
+        }
+        return ended_ok;
+    }
+};
+
+fn atoi(a: []const u8) i32 {
+    var i : i32 = 0;
+    var mul : i32 = 1;
+    var start : usize = 0;
+    if (a[0] == '-' or a[0] == '+') {
+        start = 1;
+        if (a[0] == '-') {
+            mul *= -1;
+        }
+    }
+    for(a[start..]) |v, k| {
+        if (! std.ascii.isDigit(v)) {
+            std.log.warn("Byte {x} is not a digit", .{v});
+            continue;
+        }
+        // 48 is '0' in ascii
+        std.debug.assert(v >= 48 and v < 58);
+        i += @as(i32, @as(i32, (v - 48)) * std.math.pow(i32, 10, @intCast(i32, a.len - k - 1 - start)));
+    }
+    //std.log.debug("{x} --> {}", .{a, i});
+    return i * mul;
+}
+
+test "atoi_regular" {
+    var i = atoi("1234");
+    std.testing.expectEqual(i, 1234);
+}
+
+test "atoi_pos" {
+    var i = atoi("+1234");
+    std.testing.expectEqual(i, 1234);
+}
+
+test "atoi_neg" {
+    var i = atoi("-1234");
+    std.testing.expectEqual(i, -1234);
 }