1415. 长度为 n 的开心字符串中字典序第 k 小的字符串

src/main.rs

@@ -1,72 +1,61 @@
-use std::cmp::{max, Reverse};
-use std::collections::BinaryHeap;
 
 struct Solution;
 mod arr;
-#[derive(Debug)]
-struct Node {
-    time: i32,
-    cnt: i32,
-}
-impl Node {
-    fn new(time: i32, cnt: i32) -> Node {
-        Node { time,cnt }
-    }
-    fn total(&self) -> i64 {
-        let cnt = self.cnt as i64;
-        self.time as i64 * cnt * (cnt + 1) / 2
-    }
-}
-
-impl Ord for Node {
-    // 默认的比较方式
-    fn cmp(&self, other: &Self) -> std::cmp::Ordering {
-        self.total().cmp(&other.total())
-    }
-}
-
-impl PartialOrd for Node {
-    fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
-        Some(self.total().cmp(&other.total()))
-    }
-}
-
-impl Eq for Node { }
-
-impl PartialEq for Node {
-    fn eq(&self, other: &Self) -> bool {
-        self.total() == other.total()
-    }
-
-    fn ne(&self, other: &Self) -> bool {
-        self.total() != other.total()
-    }
-}
 impl Solution {
-    pub fn min_number_of_seconds(mountain_height: i32, worker_times: Vec<i32>) -> i64 {
-        let mut heap = BinaryHeap::<Reverse<Node>>::new();
-        for x in worker_times {
-            heap.push(Reverse(Node::new(x, 1)));
+    pub fn construct(s: &mut Vec<char>, n: usize)  {
+        for _ in s.len()..n {
+            if s[s.len() - 1] == 'a' {
+                s.push('b');
+            } else {
+                s.push('a');
             }
-        for _ in 0..mountain_height {
-            let mut node = heap.pop().unwrap();
-            node.0.cnt += 1;
-            heap.push(node);
         }
-        let mut ans = 0_i64; 
-        while !heap.is_empty() {
-            let mut node = heap.pop().unwrap().0;
-            node.cnt -= 1;
-            ans = max(ans, node.total())
     }
-        ans
+    pub fn get_happy_string(n: i32, k: i32) -> String {
+        let n = n as usize;
+        let mut x =  vec!['a'];
+        Self::construct(&mut x,n);
+        for _ in 1..k {
+            let mut have_ans = false;
+            for j in (0..n).rev() {
+                if x[j] == 'a' {
+                    have_ans = true;
+                    if j == 0{
+                        x = vec!['b'];
+                        Self::construct(&mut x,n);
+                        break;
+                    }
+                    if x[j-1] == 'b'{
+                        x[j] = 'c';
+                    }else {
+                        x[j] = 'b';
+                    }
+                    x = x[0..j+1].to_vec();
+                    Self::construct(&mut x,n);
+                    break;
+                }
+                if x[j] == 'b' {
+                    if j == 0 || x[j-1] != 'c' {
+                        x[j] = 'c';
+                        x = x[0..j+1].to_vec();
+                        Self::construct(&mut x,n);
+                        have_ans = true;
+                        break;
+                    }
+                }
+            }
+            if !have_ans {
+                return String::new();
+            }
+        }
+        x.into_iter().collect()
     }
 }
 
 fn main() {
-    let result = Solution::min_number_of_seconds(
-        5,
-        vec![1, 7],
+    let result = Solution::get_happy_string(
+        10,
+        100,
     );
     println!("{:?}", result);
 }