Add an example for ABC122-C

qryxip · qryxip · commit 9f74ad563b1c · 2020-05-19T00:20:07.000+09:00
diff --git a/examples/abc122-c.rs b/examples/abc122-c.rs
@@ -0,0 +1,40 @@
+// https://atcoder.jp/contests/abc122/tasks/abc122_c
+//
+// 以下のクレートを使用。
+//
+// - `itertools-num`
+// - `proconio`
+
+use itertools_num::ItertoolsNum as _;
+use proconio::marker::{Bytes, Usize1};
+use proconio::{fastout, input};
+
+use std::iter;
+
+// `#[proconio::fastout]`で`println!`を置き換える。
+//
+// https://docs.rs/proconio-derive/0.1/proconio_derive/attr.fastout.html
+#[fastout]
+fn main() {
+    // `proconio::input!`では使わない値を`_`とすることができる。
+    //
+    // https://docs.rs/proconio/0.3.6/proconio/macro.input.html
+    input! {
+        _: usize,
+        q: usize,
+        s: Bytes,
+        lrs: [(Usize1, Usize1); q],
+    }
+
+    // `<_ as itertools_num::ItertoolsNum>::cumsum`で作られた一次元累積和のイテレータを、先頭に`0`を挿入した上で`Vec<_>`にする。
+    //
+    // https://docs.rs/itertools-num/0.1/itertools_num/trait.ItertoolsNum.html#method.cumsum
+    let cumsum = iter::once(0)
+        .chain(s.windows(2).map(|w| (w == b"AC").into()))
+        .cumsum()
+        .collect::<Vec<u32>>();
+
+    for (l, r) in lrs {
+        println!("{}", cumsum[r] - cumsum[l]);
+    }
+}
diff --git a/test-examples.toml b/test-examples.toml
@@ -100,6 +100,13 @@ url = "https://atcoder.jp/contests/abc121/tasks/abc121_b"
 matching = "Words"
 meta = { using = ["whiteread"] }
 
+[examples.abc122-c]
+type = "Normal"
+name = "ABC122: C - GeT AC"
+url = "https://atcoder.jp/contests/abc122/tasks/abc122_c"
+matching = "Words"
+meta = { using = ["itertools-num", "proconio"] }
+
 [examples.abc129-f]
 type = "Normal"
 name = "ABC129: F - Takahashi's Basics in Education and Learning"
