complete 1024.rs 1063.rs 1108.rs 1111.rs 3086.rs 7695.rs 17256.rs 17371.rs 27634.rs 31846.rs

storage/zeta/rs/completed/1111.rs

@@ -0,0 +1,73 @@
+use std::io::stdin;
+
+fn main() {
+    let mut line = String::new();
+    stdin().read_line(&mut line).unwrap();
+    let n = line.trim().parse::<usize>().unwrap();
+
+    line.clear();
+
+    stdin().read_line(&mut line).unwrap();
+    let arr = line
+        .trim()
+        .split(' ')
+        .map(|x| x.parse::<i32>().unwrap())
+        .collect::<Vec<i32>>();
+
+    if n <= 1 {
+        println!("A");
+    } else if n == 2 {
+        if arr[0] == arr[1] {
+            println!("{}", arr[0]);
+        } else {
+            println!("A");
+        }
+    } else {
+        if arr[0] == arr[1] {
+            let same_flag = arr.iter().all(|&x| x == arr[0]);
+
+            if same_flag {
+                println!("{}", arr[0]);
+            } else {
+                println!("B");
+            }
+        } else {
+            if arr[1] == arr[2] {
+                for i in 2..n - 1 {
+                    if arr[i + 1] == arr[i] {
+                        continue;
+                    } else {
+                        println!("B");
+                        return;
+                    }
+                }
+                println!("{}", arr[n - 1]);
+            } else {
+                let d_a = arr[2] - arr[1];
+                let d_b = arr[1] - arr[0];
+
+                if d_a % d_b == 0 {
+                    let a = d_a / d_b;
+                    let b = arr[1] - a * arr[0];
+                    let mut flag = true;
+                    for i in 1..n - 1 {
+                        if arr[i + 1] == arr[i] * a + b {
+                            continue;
+                        } else {
+                            flag = false;
+                            break;
+                        }
+                    }
+
+                    if flag {
+                        println!("{}", arr[n - 1] * a + b);
+                    } else {
+                        println!("B");
+                    }
+                } else {
+                    println!("B");
+                }
+            }
+        }
+    }
+}