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
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
|
use std::cmp::max;
use std::collections::HashMap;
#[derive(Debug, Clone)]
struct Node {
name: u16,
rate: usize,
neighbors: Vec<u16>
}
#[derive(Debug, Copy, Clone)]
struct MapState {
valves: usize,
pos_ind: usize,
max_pos: usize
}
#[derive(Debug, Clone)]
struct Map {
index: HashMap<u16, usize>,
nodes: Vec<Node>
}
fn getname(line: &str) -> u16 {
100 * (line.chars().nth(0).unwrap() as u16) +
(line.chars().nth(1).unwrap() as u16)
}
impl Node {
fn from_line(line: &str) -> Node {
let name = getname(&line[6..]);
let j = line.find(';').unwrap();
let rate = line[23..j].parse::<usize>().unwrap();
let mut neighbors = vec![];
let mut i = j+24;
// "tunnels lead to valves" vs "tunnel lead to valve"
// What kind of sadistic animal made these inputs?
if line.chars().nth(i).unwrap() == ' ' { i += 1; }
while i < line.len() {
neighbors.push(getname(&line[i..]));
i += 4;
}
Node { name, rate, neighbors }
}
}
impl Map {
fn from_stdin() -> Map {
let mut line = String::new();
let mut nodes = Vec::<Node>::new();
while std::io::stdin().read_line(&mut line).unwrap() > 0 {
let node = Node::from_line(&line);
if nodes.len() > 0 && node.name == getname("AA") {
nodes.push(nodes[0].clone());
nodes[0] = node;
} else {
nodes.push(node);
}
line.clear();
}
let index = nodes.iter()
.enumerate()
.map(|(i, n)| (n.name, i))
.collect::<HashMap<_, _>>();
Map { index, nodes }
}
fn state_max(&self) -> usize {
let mut i: usize = 0;
let mut tot: usize = 0;
for n in &self.nodes {
if n.rate == 0 { continue; }
tot += 1 << i;
i += 1;
}
let len = self.nodes.len();
tot * len + len
}
fn released_pressure(&self) -> usize {
self.nodes.iter()
.map(|n| if n.valve_on { n.rate } else { 0 })
.sum()
}
fn most_pressure(&self, minutes: usize) -> usize {
let n = self.state_max();
let mut t = vec![0 as usize; n];
let mut u = vec![0 as usize; n];
let mut map = self.clone();
// Setup table for last minute
for s in 0..n {
map.set_state(s);
t[s] = map.released_pressure();
}
// Dynamic programming counting back to 0 minutes
for i in (0..minutes).rev() {
// Double buffer technique so we don't have to swap vectors
let (current, next) = if i % 2 == minutes % 2 {
(&mut t, &mut u)
} else {
(&mut u, &mut t)
};
for s in 0..n {
map.set_state(s);
let pos = map.pos;
let mut k = 0;
let ind = map.index[&pos];
let p = map.released_pressure();
// Try turning on the valve
if map.nodes[ind].rate > 0 && !map.nodes[ind].valve_on {
map.nodes[ind].valve_on = true;
k = max(k, p + next[map.get_state()]);
map.nodes[ind].valve_on = false;
}
// Try moving to a neighbor
for v in &map.nodes[ind].neighbors {
map.pos = *v;
k = max(k, p + next[map.get_state()]);
}
current[s] = k;
}
}
if 0 == minutes % 2 { t[0] } else { u[0] }
}
}
fn main() {
let map = Map::from_stdin();
println!("{}", map.most_pressure(29));
}
|
