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#![allow(dead_code)]
#![allow(unused_variables)]
#![allow(unused_mut)]
use std::env;
use std::fs::File;
use std::io::Read;
#[derive(Debug, PartialEq, Clone)]
struct Block {
isfile: bool,
id: u64,
}
fn print_fs(fs: &Vec<Block>) {
for b in fs {
if b.isfile {
print!("{}", b.id);
} else {
print!(".");
}
}
println!();
}
fn compact(mut fs: Vec<Block>) -> Vec<Block> {
for i in (0..fs.len()).rev() {
if !fs[i].isfile {
continue;
}
for j in 0..fs.len() {
if i < j {
break;
}
if !fs[j].isfile {
fs.swap(i, j);
break;
}
}
}
fs
}
fn same(index: usize, fs: &Vec<Block>) -> (usize, usize) {
let mut start: usize = 0;
let mut end: usize = 0;
let b = &fs[index];
for e in index..fs.len() {
if fs[e].isfile == b.isfile && (!fs[e].isfile || fs[e].id == b.id) {
end = e;
} else {
break;
}
}
for s in (0..=index).rev() {
if fs[s].isfile == b.isfile && (!fs[s].isfile || fs[s].id == b.id) {
start = s;
} else {
break;
}
}
return (start, end - start + 1);
}
fn compact2(mut fs: Vec<Block>) -> Vec<Block> {
let mut i = fs.len() - 1;
loop {
let mut il;
(i, il) = same(i, &fs);
if !fs[i].isfile {
if i == 0 {
break;
}
i -= 1;
continue;
}
let mut j = 0;
let mut jl;
loop {
(j, jl) = same(j, &fs);
if j > i {
break;
}
if fs[j].isfile || il > jl {
if j + jl >= fs.len() {
break;
}
j = j + jl;
continue;
}
for r in 0..il {
fs.swap(i + r, j + r);
}
if j + jl >= fs.len() {
break;
}
j = j + jl;
}
if i == 0 {
break;
}
i -= 1;
}
fs
}
fn checksum(fs: &Vec<Block>) -> u64 {
let mut sum = 0;
for i in (0..fs.len()).rev() {
if fs[i].isfile {
sum += (i as u64) * fs[i].id;
}
}
return sum;
}
fn main() {
let args: Vec<String> = env::args().collect();
let filename = if args.len() == 1 {
"in/".to_owned() + args[0].split('/').last().unwrap() + ".pzl"
} else {
args[1].clone()
};
let mut f = File::open(filename).expect("cannot open file");
let mut content = String::new();
f.read_to_string(&mut content).expect("cannot read file");
let mut lines = content.trim_end().split("\n");
let line = lines.next().unwrap();
let mut fs: Vec<Block> = Vec::new();
let mut isfile = true;
let mut id = 0;
for (i, c) in line.chars().enumerate() {
let n = c.to_digit(10).unwrap() as usize;
for j in 0..n {
let b = Block {
isfile: isfile,
id: id,
};
fs.push(b);
}
if isfile {
id += 1;
}
isfile ^= true;
}
//print_fs(&fs);
let fs1 = compact(fs.clone());
//print_fs(&fs1);
let res1 = checksum(&fs1);
//print_fs(&fs);
let fs2 = compact2(fs.clone());
//print_fs(&fs2);
let res2 = checksum(&fs2);
println!("res1: {}", res1);
println!("res2: {}", res2);
assert_eq!(res1, 6370402949053);
assert_eq!(res2, 6398096697992);
}
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