math-and-algorithm 086-088

math-and-algorithm/src/bin/086.rs

@@ -1,10 +1,23 @@
-use proconio::{input, marker::Usize1};
+use proconio::{input, marker::Chars};
 
 fn main() {
     input! {
-        n: usize,
-        a: [Usize1; n],
+        _n: usize,
+        s: Chars,
     };
-    let ans = n - a.len();
-    println!("{}", ans);
+    let ans = (|| {
+        let mut depth = 0_i64;
+        for s_i in s {
+            match s_i {
+                '(' => depth += 1,
+                ')' => depth -= 1,
+                _ => unreachable!(),
+            }
+            if depth < 0 {
+                return false;
+            }
+        }
+        depth == 0
+    })();
+    println!("{}", if ans { "Yes" } else { "No" });
 }

math-and-algorithm/src/bin/087.rs

@@ -1,10 +1,11 @@
-use proconio::{input, marker::Usize1};
+use proconio::input;
 
 fn main() {
     input! {
         n: usize,
-        a: [Usize1; n],
     };
-    let ans = n - a.len();
+    let modp = 1_000_000_007;
+    let x = (1 + n) * n / 2 % modp;
+    let ans = x * x % modp;
     println!("{}", ans);
 }

math-and-algorithm/src/bin/088.rs

@@ -1,10 +1,13 @@
-use proconio::{input, marker::Usize1};
+use proconio::input;
 
 fn main() {
     input! {
-        n: usize,
-        a: [Usize1; n],
+        a: usize,
+        b: usize,
+        c: usize,
     };
-    let ans = n - a.len();
+    let modp = 998_244_353;
+    let f = |x| (x + 1) * x / 2 % modp;
+    let ans = f(a) * f(b) % modp * f(c) % modp;
     println!("{}", ans);
 }