1 files changed, 45 insertions, 0 deletions
diff --git a/src/day-3/part-2.zig b/src/day-3/part-2.zig
new file mode 100644
index 0000000..df78ed1
--- /dev/null
+++ b/src/day-3/part-2.zig
@@ -0,0 +1,45 @@
+const std = @import("std");
+
+//returns index
+pub fn largest(line: []const u8, start: usize, end: usize) usize {
+    var idx: usize = start;
+
+    for(start..end) |i| {
+        if(line[i] > line[idx]){
+            idx = i;
+        }
+    }
+
+    return idx;
+} 
+
+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: [256]u8 = undefined;
+
+    var total: u64 = 0;
+
+    const need = 12;
+    while(try reader.readUntilDelimiterOrEof(&buffer, '\n')) |line| {
+        var lastidx: usize = 0;
+        var n: u64 = 0;
+
+        for(1 .. need + 1) |i| {
+            lastidx = largest(line, lastidx, line.len - (need - i));
+            n += std.math.pow(u64, 10, need - i) * (line[lastidx] - '0');
+            lastidx += 1;
+        }
+
+        total += n;
+    }
+
+    std.debug.print("{d}\n", .{total});
+}