add abc406c.rs

Author: rchaser53

src/abc/abc406c.rs

@@ -0,0 +1,45 @@
+/** THIS IS AN OUTPUT FILE. NOT EDIT THIS FILE DIRECTLY. **/
+use proconio::input;
+use proconio::marker::*;
+use std::marker::PhantomData;
+use std::cmp::*;
+use std::collections::*;
+
+fn main() {
+  input! {
+    n:usize,
+    a:[usize;n]
+  }
+  
+  let mut vec = vec![];
+  let mut rev = '<';
+  let mut count = 0;
+  for i in 0..n-1 {
+    if a[i] < a[i+1] {
+      if rev == '>' {
+        vec.push(count);
+        rev = '<';
+        count = 0;
+      }
+    } else {
+      if rev == '<' {
+        vec.push(count);
+        rev = '>';
+        count = 0;
+      }
+    }
+    count += 1;
+  }
+
+  vec.push(count);
+  if rev == '>' {
+    vec.push(0);
+  }
+  
+  let mut result = 0usize;
+  for i in (2..vec.len()).step_by(2) {
+    result += vec[i] * vec[i-2];
+  }
+
+  println!("{}", result);
+}