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const std = @import("std");
const day2 = @import("day2");
fn isInvalid(str: []const u8, substr_len: u64) bool {
const substr = str[0..substr_len];
var i: u64 = 0;
while (i < str.len) {
if (i + substr_len > str.len) {
return false;
}
if (!std.mem.eql(u8, substr, str[i .. i + substr_len])) {
return false;
}
i += substr_len;
}
return true;
}
test "is invalid" {
try std.testing.expect(isInvalid("11", 1) == true);
try std.testing.expect(isInvalid("22", 1) == true);
try std.testing.expect(isInvalid("1010", 2) == true);
try std.testing.expect(isInvalid("1010", 1) == false);
try std.testing.expect(isInvalid("12341234", 1) == false);
try std.testing.expect(isInvalid("12341234", 2) == false);
try std.testing.expect(isInvalid("12341234", 3) == false);
try std.testing.expect(isInvalid("12341234", 4) == true);
try std.testing.expect(isInvalid("123123123", 1) == false);
try std.testing.expect(isInvalid("123123123", 2) == false);
try std.testing.expect(isInvalid("123123123", 3) == true);
try std.testing.expect(isInvalid("123123123", 4) == false);
try std.testing.expect(isInvalid("123123123", 5) == false);
try std.testing.expect(isInvalid("111", 1) == true);
try std.testing.expect(isInvalid("111", 2) == false);
try std.testing.expect(isInvalid("1212121212", 1) == false);
try std.testing.expect(isInvalid("1212121212", 2) == true);
try std.testing.expect(isInvalid("1212121212", 3) == false);
try std.testing.expect(isInvalid("1111111", 1) == true);
try std.testing.expect(isInvalid("1111111", 2) == false);
}
fn numDigits(x: u64) usize {
if (x == 0) {
return 1;
}
return std.math.log10_int(x) + 1;
}
pub fn main() !void {
// Initiate allocator
var gpa = std.heap.GeneralPurposeAllocator(.{}){};
defer _ = gpa.deinit();
const alloc = gpa.allocator();
// Read contents from file "./filename"
const cwd = std.fs.cwd();
const fileContents = try cwd.readFileAlloc(alloc, "day2.txt", 20000);
defer alloc.free(fileContents);
// Print file contents
// std.debug.print("{s}", .{fileContents});
var splits = std.mem.splitScalar(u8, fileContents, ',');
var invalid: u64 = 0;
while (splits.next()) |chunk| {
if (chunk.len < 1) {
continue;
}
const ws = " \t\r\n";
var it = std.mem.splitScalar(u8, chunk, '-');
var startStr = it.next() orelse return error.invalid;
var endStr = it.next() orelse return error.invalid;
startStr = std.mem.trim(u8, startStr, ws);
endStr = std.mem.trim(u8, endStr, ws);
const start = std.fmt.parseInt(u64, startStr, 10) catch {
std.debug.panic("invalid integer: '{s}'\n", .{startStr});
};
const end = std.fmt.parseInt(u64, endStr, 10) catch {
std.debug.panic("invalid integer: '{s}'\n", .{endStr});
};
std.debug.print("start:{} end:{} | ", .{ start, end });
for (start..end + 1) |i| {
// std.debug.print("i:{} | ", .{i});
for (1..@divTrunc(numDigits(i), 2) + 1) |j| {
// std.debug.print("j:{} ; ", .{j});
const str = try std.fmt.allocPrint(
alloc,
"{d}",
.{i},
);
defer alloc.free(str);
if (isInvalid(str, j)) {
invalid += i;
std.debug.print("{}, ", .{i});
break;
}
}
}
std.debug.print("| invalid:{} \n", .{invalid});
}
// Prints to stderr, ignoring potential errors.
std.debug.print("Sum of invalids: {}\n", .{invalid});
try day2.bufferedPrint();
}
|
