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
38
39
40
41
42
43
44
45
|
use std::io;
use std::io::BufRead;
use std::ops::Range;
fn power(x: i32, y: i32, serial: i32) -> i32 {
(y * (x + 10) + serial) * (x + 10) / 100 % 10 - 5
}
fn optimise(grid: [[i32; 300]; 300], srange: Range<usize>) -> (usize, usize, usize) {
let mut maxval = i32::min_value();
let mut maxat = (0, 0, 0);
for s in srange {
for y in 0..301-s {
for x in 0..301-s {
let tot = (0..s).map(|dy| (0..s).map(|dx| grid[y+dy][x+dx]).sum::<i32>()).sum();
if tot > maxval {
maxval = tot;
maxat = (x, y, s);
}
}
}
}
maxat
}
pub fn main<T: BufRead>(reader: T) -> io::Result<(String, String)> {
let serial = reader.lines().next().unwrap().unwrap().parse::<i32>().unwrap();
let mut grid = [[0; 300]; 300];
for y in 0..300 {
for x in 0..300 {
grid[y][x] = power(x as i32, y as i32, serial);
}
}
let maxat = optimise(grid, 3..4);
let part1 = format!("{},{}", maxat.0, maxat.1);
let maxat = optimise(grid, 1..301);
let part2 = format!("{},{},{}", maxat.0, maxat.1, maxat.2);
Ok((part1, part2))
}
|
