1

Author: Ainevsia

notes/src/day11/lc20.md

@@ -41,4 +41,30 @@ impl Solution {
 }
 ```
 
-## 学习感想
+## 学习感想
+
+
+```rust
+
+struct Solution {}
+impl Solution {
+    pub fn is_valid(s: String) -> bool {
+        let mut stack: Vec<char> = Vec::new();
+        for c in s.chars() {
+            if ['{', '(', '['].contains(&c) {
+                stack.push(c);
+            } else {
+                if let Some(x) = stack.pop() {
+                    if x == '{' && c != '}' { return false }
+                    else if x == '(' && c != ')' { return false }
+                    else if x == '[' && c != ']' { return false }
+                } else {
+                    return false
+                }
+            }
+        }
+        stack.is_empty()
+    }
+}
+
+```

notes/src/day13/lc239.md

@@ -38,4 +38,33 @@ impl Solution {
 
 ## 学习感想
 
-一开始确实以为大顶堆就行了，其实要用单调栈，之前也有做过单调栈的题目
+一开始确实以为大顶堆就行了，其实要用单调栈，之前也有做过单调栈的题目
+
+单调队列是不能够删除一个指定的元素的，单调栈里维护需要的最大值
+
+```rust
+struct Solution {}
+impl Solution {
+    pub fn max_sliding_window(nums: Vec<i32>, k: i32) -> Vec<i32> {
+        use std::collections::VecDeque;
+        let mut v: VecDeque<i32> = VecDeque::new();
+        let k: usize = k as usize;
+        let mut res: Vec<i32> = vec![];
+        for idx in 0 .. nums.len() {
+            if idx >= k  {
+                let to_delete: i32 = nums[idx - k];
+                if to_delete == v[0] { v.pop_front(); }
+            }
+            let cur: i32 = nums[idx];
+            while let Some(&bck) = v.back() {
+                if bck < cur {
+                    v.pop_back();
+                } else { break }
+            }
+            v.push_back(cur);
+            if idx >= k - 1 { res.push(v[0]); }
+        }
+        res
+    }
+}
+```

notes/src/day13/lc347.md

@@ -39,4 +39,31 @@ impl Solution {
 
 ## 学习感想
 
-map+小顶堆
+map+小顶堆
+
+
+
+```rust
+struct Solution {}
+
+impl Solution {
+    pub fn top_k_frequent(nums: Vec<i32>, k: i32) -> Vec<i32> {
+        use std::collections::{HashMap, BinaryHeap};
+        let mut map: HashMap<i32, usize> = HashMap::new();
+        nums.iter().for_each(|&i| {
+            map.entry(i).and_modify(|x| *x += 1usize).or_default();
+        });
+        let mut res: Vec<i32> = Vec::new();
+        let mut pq: BinaryHeap<(usize, i32)> = BinaryHeap::new();
+        for (k, v) in map {
+            pq.push((v, k));
+        }
+        (0i32 .. k) .for_each(|_| {
+            res.push(pq.pop().unwrap().1);
+        });
+        res
+    }
+}
+
+
+```