update

Author: caibirdme

src/lib.rs

@@ -28,6 +28,7 @@ mod prob_10;
 mod prob_16;
 mod prob_18;
 mod prob_21;
+mod prob_22;
 mod prob_27;
 mod prob_29;
 mod prob_30;

src/prob_22.rs

@@ -0,0 +1,28 @@
+impl Solution {
+    pub fn generate_parenthesis(n: i32) -> Vec<String> {
+        let mut tmp = vec![];
+        let mut ans = vec![];
+        Self::dfs(n, 0, &mut tmp, &mut ans);
+        ans
+    }
+    fn dfs(n: i32, open: i32, tmp: &mut Vec<u8>, ans: &mut Vec<String>) {
+        if n == 0 {
+            for _ in 0..open {
+                tmp.push(b')');
+            }
+            ans.push(unsafe {std::str::from_utf8_unchecked(&tmp).to_string()});
+            tmp.truncate(tmp.len()-(open as usize));
+            return;
+        }
+        if open > 0 {
+            tmp.push(b')');
+            Self::dfs(n, open-1, tmp, ans);
+            tmp.pop();
+        }
+        tmp.push(b'(');
+        Self::dfs(n-1, open+1, tmp, ans);
+        tmp.pop();
+    }
+}
+
+struct Solution;

src/prob_406.rs

@@ -1,50 +1,21 @@
-use std::collections::BinaryHeap;
-use std::cmp::{Ordering, Reverse};
-
 impl Solution {
-    pub fn reconstruct_queue(people: Vec<Vec<i32>>) -> Vec<Vec<i32>> {
-        if people.len() <= 1 {
+    pub fn reconstruct_queue(mut people: Vec<Vec<i32>>) -> Vec<Vec<i32>> {
+        let n = people.len();
+        if n <= 1 {
             return people;
         }
-        let mut heap = BinaryHeap::new();
-        for item in people {
-            heap.push(Reverse(Pair(item[0], item[1])));
-        }
-        let n = heap.len();
-        let mut ans: Vec<Option<Vec<i32>>> = vec![None; n];
-        while !heap.is_empty() {
-            let cur = heap.pop().unwrap().0;
-            let mut count = 0;
-            let mut idx = 0;
-            while cur.1 > count {
-                if ans[idx].is_none() {
-                    count+=1;
-                }
-                idx+=1;
+        people.sort_by(|a,b| {
+            if a[0] == b[0] {
+                a[1].cmp(&b[1])
+            } else {
+                b[0].cmp(&a[0])
             }
-            while idx < n && ans[idx].is_some() {idx+=1;}
-            ans[idx] = Some(vec![cur.0, cur.1]);
-        }
-        ans.into_iter().map(|x| x.unwrap()).collect()
-    }
-}
-
-#[derive(Eq, PartialEq, Copy, Clone)]
-struct Pair(i32, i32);
-
-impl Ord for Pair {
-    fn cmp(&self, other: &Self) -> Ordering {
-        let t = self.0.cmp(&other.0);
-        match t {
-            Ordering::Equal => other.1.cmp(&self.1),
-            _ => t,
+        });
+        let mut ans = vec![];
+        for item in people {
+            ans.insert(item[1] as usize, item);
         }
-    }
-}
-
-impl PartialOrd for Pair {
-    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
-        Some(self.cmp(other))
+        ans
     }
 }
 
@@ -60,7 +31,7 @@ mod tests {
             (vec![vec![1,1], vec![2,0]], vec![vec![2,0], vec![1,1]]),
         ];
         for (num, expect) in test_cases {
-            assert_eq!(expect, Solution::reconstruct_queue(num.clone()), "num: {:?}", num);
+            assert_eq!(Solution::reconstruct_queue(num.clone()), expect, "num: {:?}", num);
         }
     }
 }