blob: 974edf2d022ccd504fb366d50e5a85c22fe1088a (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
|
const std = @import("std");
const File = std.fs.File;
pub fn main() !void {
const stdout = std.io.getStdOut().writer();
const argv = std.os.argv;
const file = try switch (argv.len) {
1 => std.io.getStdIn(),
2 => try std.fs.cwd().openFileZ(argv[1], File.OpenFlags{}),
else => error.InvalidArguments,
};
defer file.close();
try stdout.print("{}\n", .{try findMissing(&file)});
}
fn findMissing(file: *const File) !u32 {
const in = file.reader();
var buf: [10]u8 = undefined;
var min: u32 = std.math.maxInt(u32);
var max: u32 = 0;
var sum: u32 = 0;
while (try in.readUntilDelimiterOrEof(buf[0..], ',')) |number| {
var n = try std.fmt.parseInt(u32, number, 10);
sum += n;
if (n < min) min = n;
if (n > max) max = n;
try in.skipUntilDelimiterOrEof('\n');
}
const sumWithoutMissing = @divExact((max - min + 1) * (max + min), 2);
return sumWithoutMissing - sum;
}
|
