complete 9414.rs 17392.rs 26853.rs

storage/zeta/rs/completed/17392.rs

@@ -0,0 +1,30 @@
+use std::io::{read_to_string, stdin};
+
+fn main() {
+    let temp = read_to_string(stdin()).unwrap();
+    let mut iter = temp
+        .split_ascii_whitespace()
+        .map(|x| x.parse::<i64>().unwrap());
+
+    let n = iter.next().unwrap();
+    let m = iter.next().unwrap();
+
+    let total_expected_happinesses: i64 = (0..n).map(|_| iter.next().unwrap()).sum();
+
+    let res = if total_expected_happinesses + n >= m {
+        0
+    } else {
+        let actual_non_happy_day = m - (total_expected_happinesses + n);
+        let d = actual_non_happy_day / (n + 1);
+        let remain = actual_non_happy_day % (n + 1);
+
+        if remain > 0 {
+            remain * ((d + 1) * (d + 2) * (2 * d + 3) / 6)
+                + (n + 1 - remain) * (d * (d + 1) * (2 * d + 1) / 6)
+        } else {
+            (d * (d + 1) * (2 * d + 1) / 6) * (n + 1)
+        }
+    };
+
+    println!("{}", res);
+}