Added sample code for D - Maxflow

Author: TonalidadeHidrica

examples/practice2_d_maxflow.rs

@@ -0,0 +1,63 @@
+use ac_library_rs::MfGraph;
+use std::io::Read;
+use std::iter;
+
+fn main() {
+    const N: usize = 128;
+
+    let mut buf = String::new();
+    std::io::stdin().read_to_string(&mut buf).unwrap();
+    let mut input = buf.split_whitespace();
+
+    let n: usize = input.next().unwrap().parse().unwrap();
+    let m: usize = input.next().unwrap().parse().unwrap();
+    let mut s = vec![vec![false; N]; N];
+    for i in 1..=n {
+        for (j, c) in (1..=m).zip(input.next().unwrap().chars()) {
+            s[i][j] = c == '.';
+        }
+    }
+
+    let dy = [1, 0, -1, 0];
+    let dx = [0, 1, 0, -1];
+    let c = "v>^<".chars().collect::<Vec<_>>();
+    let mut graph = MfGraph::<i32>::new(128 * 128);
+
+    for i in 1..=n {
+        for j in 1..=m {
+            if (i + j) % 2 == 0 {
+                graph.add_edge(0, i * N + j, 1);
+                for (dy, dx) in dy.iter().zip(dx.iter()) {
+                    let k = (i as i32 + dy) as usize;
+                    let l = (j as i32 + dx) as usize;
+                    if s[i][j] && s[k][l] {
+                        graph.add_edge(i * N + j, k * N + l, 1);
+                    }
+                }
+            } else {
+                graph.add_edge(i * N + j, 1, 1);
+            }
+        }
+    }
+    println!("{}", graph.flow(0, 1));
+    let mut res: Vec<Vec<_>> = (1..=n)
+        .map(|i| (1..=m).map(|j| if s[i][j] { '.' } else { '#' }).collect())
+        .collect();
+    for e in graph.edges() {
+        let i = e.from / N;
+        let j = e.from % N;
+        let k = e.to / N;
+        let l = e.to % N;
+        if e.flow == 1 {
+            for h in 0..4 {
+                if i as i32 + dy[h] == k as i32 && j as i32 + dx[h] == l as i32 {
+                    res[i - 1][j - 1] = c[h];
+                    res[k - 1][l - 1] = c[h ^ 2];
+                }
+            }
+        }
+    }
+    for s in res {
+        println!("{}", s.iter().collect::<String>());
+    }
+}