Add union-find crate

Cargo.toml

@@ -133,6 +133,9 @@ im-rc = "=14.0.0"
 fixedbitset = "=0.2.0"
 bitset-fixed = "=0.1.0"
 
+# union-find (a.k.a. disjoint-set)
+union-find = "=0.3.2"
+
 # 競技プログラミングの入出力サポート
 proconio = { version = "=0.3.4", features = ["derive"] }
 text_io = "=0.1.7"

examples/abc120-d.rs

@@ -0,0 +1,29 @@
+// https://atcoder.jp/contests/abc120/tasks/abc120_d
+
+use proconio::marker::Usize1;
+use proconio::{fastout, input};
+use union_find::{QuickFindUf, UnionBySize, UnionFind as _};
+
+#[fastout]
+fn main() {
+    input! {
+        n: usize,
+        m: usize,
+        abs: [(Usize1, Usize1); m],
+    }
+
+    let mut u = QuickFindUf::<UnionBySize>::new(n);
+    let mut k = n * (n - 1) / 2;
+    let mut r = vec![k];
+    r.extend(abs.into_iter().rev().map(|(a, b)| {
+        let p = u.get(a).size() * u.get(b).size();
+        if u.union(a, b) {
+            k -= p;
+        }
+        k
+    }));
+    assert_eq!(r.pop(), Some(0));
+    for r in r.into_iter().rev() {
+        println!("{}", r);
+    }
+}

examples/tests.ron

@@ -12,5 +12,9 @@
             name: "ABC049 / ARC065: C - 白昼夢 / Daydream",
             matching: ExactWords,
         ),
+        "abc120-d": (
+            name: "ABC120: D - Decayed Bridges ",
+            matching: ExactWords,
+        ),
     }
 )

examples/testsets/abc120-d/in/sample_01.txt

@@ -0,0 +1,6 @@
+4 5
+1 2
+3 4
+1 3
+2 3
+1 4

examples/testsets/abc120-d/in/sample_02.txt

@@ -0,0 +1,6 @@
+6 5
+2 3
+1 2
+5 6
+3 4
+4 5

examples/testsets/abc120-d/in/sample_03.txt

@@ -0,0 +1,2 @@
+2 1
+1 2

examples/testsets/abc120-d/out/sample_01.txt

@@ -0,0 +1,5 @@
+0
+0
+4
+5
+6

examples/testsets/abc120-d/out/sample_02.txt

@@ -0,0 +1,5 @@
+8
+9
+12
+14
+15

examples/testsets/abc120-d/out/sample_03.txt

@@ -0,0 +1 @@
+1

tools/test-with-generated-opts/src/main.rs

@@ -179,8 +179,7 @@ fn test(task_name: &str, matching: Matching, testsets: &Path, binary: &Path) ->
             .with_context(|| format!("Failed to execute {}", binary.display()))?;
 
         child.stdin.as_mut().unwrap().write_all(input.as_ref())?;
-        let status = child.wait()?;
-        let stop = Instant::now();
+        child.stdin.take();
         let actual = {
             let mut actual = "".to_owned();
             child
@@ -191,6 +190,8 @@ fn test(task_name: &str, matching: Matching, testsets: &Path, binary: &Path) ->
                 .with_context(|| format!("{} outputted invalid UTF-8", binary.display()))?;
             actual
         };
+        let status = child.wait()?;
+        let stop = Instant::now();
 
         let time = (stop - start).as_millis();
         let verdict = if status.success() && matching.accepts(&expected, &actual) {