feat: add rust codes for chapter heap (#612)

Co-authored-by: Yudong Jin <krahets@163.com>

codes/rust/chapter_heap/top_k.rs

@@ -0,0 +1,39 @@
+/*
+ * File: top_k.rs
+ * Created Time: 2023-07-16
+ * Author: night-cruise (2586447362@qq.com)
+ */
+
+include!("../include/include.rs");
+
+use std::cmp::Reverse;
+use std::collections::BinaryHeap;
+
+/* 基于堆查找数组中最大的 k 个元素 */
+fn top_k_heap(nums: Vec<i32>, k: usize) -> BinaryHeap<Reverse<i32>> {
+    // Rust 的 BinaryHeap 是大顶堆，使用 Reverse 将元素大小反转
+    let mut heap = BinaryHeap::<Reverse<i32>>::new();
+    // 将数组的前 k 个元素入堆
+    for &num in nums.iter().take(k) {
+        heap.push(Reverse(num));
+    }
+    // 从第 k+1 个元素开始，保持堆的长度为 k
+    for &num in nums.iter().skip(k) {
+        // 若当前元素大于堆顶元素，则将堆顶元素出堆、当前元素入堆
+        if num > heap.peek().unwrap().0 {
+            heap.pop();
+            heap.push(Reverse(num));
+        }
+    }
+    heap
+}
+
+/* Driver Code */
+fn main() {
+    let nums = vec![1, 7, 6, 3, 2];
+    let k = 3;
+
+    let res = top_k_heap(nums, k);
+    println!("最大的 {} 个元素为", k);
+    print_util::print_heap(res.into_iter().map(|item| item.0).collect());
+}