WA atcoder/abc327/e

Cargo.toml

@@ -826,3 +826,7 @@ path = "atcoder/abc325/d/main.rs"
 [[bin]]
 name = "atcoder-abc326-e-main"
 path = "atcoder/abc326/e/main.rs"
+
+[[bin]]
+name = "atcoder-abc327-e-main"
+path = "atcoder/abc327/e/main.rs"

atcoder/abc327/e/main.rs

@@ -0,0 +1,75 @@
+// WA
+
+// https://atcoder.jp/contests/abc327/tasks/abc327_e
+
+fn main() {
+    // n ~ 5000
+    let n: usize = read_vec()[0];
+    let ls: Vec<f64> = read_vec();
+
+    const C1: f64 = 0.9;
+    const C2: f64 = 1200.0;
+
+    // dp(n, k) = (optimal of "∑ (0.9)^(k - i) Qi" when picking "k" out of "P1" .. "Pn")
+    let mut dp: Vec<Vec<f64>> = vec![vec![f64::MIN; n + 1]; n + 1];
+    dp[0][0] = 0.0;
+    for i in 0..n {
+        for k in 0..=i {
+            let next = C1 * dp[i][k] + ls[i];
+            dp[i + 1][k + 1] = next.max(dp[i][k + 1]);
+        }
+    }
+
+    let mut result = f64::MIN;
+    for k in 1..=n {
+        let denom = (1.0 - C1.powf(k as f64)) / (1.0 - C1);
+        let next = dp[n][k] / denom - C2 / (k as f64).sqrt();
+        result = result.max(next);
+    }
+    println!("{}", result);
+}
+
+/*
+python misc/run.py atcoder/abc327/e/main.rs
+
+%%%% begin
+3
+1000 600 1200
+%%%%
+256.735020470879931
+%%%% end
+
+%%%% begin
+3
+600 1000 1200
+%%%%
+261.423219407873489
+%%%% end
+
+%%%% begin
+1
+100
+%%%%
+-1100.000000000000000
+%%%% end
+*/
+
+//
+// utils
+//
+
+#[allow(dead_code)]
+fn read_vec<T: std::str::FromStr>() -> Vec<T> {
+    let mut line = String::new();
+    std::io::stdin().read_line(&mut line).unwrap();
+    line.split_whitespace()
+        .map(|s| s.parse().ok().unwrap())
+        .collect()
+}
+
+#[allow(dead_code)]
+fn read_array<T: std::str::FromStr, const LEN: usize>() -> [T; LEN] {
+    #[allow(unused_imports)]
+    use std::convert::TryInto;
+    read_vec::<T>().try_into().ok().unwrap()
+}