Exercise2

Exercise/Homework2/Q2.rs

@@ -0,0 +1,50 @@
+use std::io::{self, Read, Write};
+
+fn main() {
+/*
+    let mut s = String::new();
+    io::stdin().read_line(&mut s).unwrap();
+    let n: usize = s.trim().parse().unwrap();
+
+    let mut nums: Vec<i64> = Vec::new();
+    let mut max: i64 = 0;
+
+    for _ in 0..n {
+        let mut x = String::new();
+        io::stdin().read_line(&mut x).unwrap();
+        let a: i64 = x.trim().parse().unwrap();
+        nums.push(a);
+        if a > max {
+            max = a;
+}*/
+//  //输入太慢了过不了
+    let mut buf = String::new();
+    io::stdin().read_to_string(&mut buf).unwrap();
+    let mut it = buf.split_whitespace();
+
+    let m: usize = it.next().unwrap().parse().unwrap();
+    let mut vec: Vec<i64> = Vec::with_capacity(m);
+    let mut max: i64 = 0;
+
+    for _ in 0..m {
+        let a: i64 = it.next().unwrap().parse().unwrap();
+        vec.push(a);
+        if a > max { max = a; }
+    }
+
+    let mut dp: Vec<i64> = vec![0; (max + 1) as usize];
+    if max >= 0 { dp[0] = 1; }
+    if max >= 1 { dp[1] = 1; }
+    if max >= 2 { dp[2] = 2; }
+    if max >= 3 { dp[3] = 4; }
+
+    for i in 4..=max {
+        dp[i as usize] = dp[(i - 1) as usize] + dp[(i - 2) as usize] + dp[(i - 3) as usize] + dp[(i - 4) as usize];
+    }
+
+    let mut out = String::new();
+    for i in vec {
+        out.push_str(&format!("{}\n", dp[i as usize]));
+    }
+    io::stdout().write_all(out.as_bytes()).unwrap();
+}