day 6

1 files changed, 79 insertions, 0 deletions

diff --git a/src/day-6/part-2.zig b/src/day-6/part-2.zig
new file mode 100644
index 0000000..a2f85f6
--- /dev/null
+++ b/src/day-6/part-2.zig
@@ -0,0 +1,79 @@
+const std = @import("std");
+
+const problem = struct {n: []u64, mult: bool};
+
+pub fn main() !void {
+    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
+    defer _ = gpa.deinit();
+    const alloc = gpa.allocator();
+    
+    const path = "input.txt";
+    const fp = try std.fs.cwd().openFile(path, .{.mode = std.fs.File.OpenMode.read_only});
+    defer fp.close();
+    var reader = fp.reader();
+
+    var buffer: [8000]u8 = undefined;
+
+    var list = std.ArrayList(problem).init(alloc);
+    defer list.deinit();
+    defer for(list.items) |v| alloc.free(v.n);
+
+    while(try reader.readUntilDelimiterOrEof(&buffer, '\n')) |line| {
+        if(line[0] == '*' or line[0] == '+'){
+            var next_mult: bool = line[0] == '*';
+            var i: usize = 1;
+            var w: usize = 1;
+
+            while(i < line.len) : ({i += 1; w += 1;}) {
+                if(line[i] != ' '){
+                    var l = try alloc.alloc(u64, w - 1);
+                    @memset(l[0..], 0);
+                    try list.append(problem{.n = l, .mult = next_mult});
+                    next_mult = line[i] == '*';
+                    w = 0; 
+                }
+            }
+            var l = try alloc.alloc(u64, w);
+            @memset(l[0..], 0);
+            try list.append(problem{.n = l, .mult = next_mult});
+        }
+    }
+
+    try fp.seekTo(0);
+    while(try reader.readUntilDelimiterOrEof(&buffer, '\n')) |line| {
+        if(line[0] == '*' or line[0] == '+') break;
+
+        var chunk: usize = 0;
+        var count: u64 = 0;
+
+        for(line) |c| {
+            if(count >= list.items[chunk].n.len + 1){
+                chunk += 1;
+                count = 0;
+            }
+
+            if(c != ' '){
+                list.items[chunk].n[count] *= 10;
+                list.items[chunk].n[count] += c - '0';
+            }
+
+            count += 1;
+            
+        }
+    }
+
+    var total: u64 = 0;
+
+    for(list.items) |v| {
+        var n: u64 = 0;
+        if(v.mult){
+            n = 1;
+            for(v.n) |a| n *= a;
+        } else {
+            for(v.n) |a| n += a;
+        }
+        total += n;
+    }
+
+    std.debug.print("{d}\n", .{total});
+}