feat: add rust solution to lc problem:No.0210 (#1595)

No.0210.Course Schedule II

Author: poltao

solution/0200-0299/0210.Course Schedule II/README.md

@@ -269,6 +269,49 @@ public class Solution {
 }
 ```
 
+### **Rust**
+
+```rust
+impl Solution {
+    pub fn find_order(num_courses: i32, prerequisites: Vec<Vec<i32>>) -> Vec<i32> {
+        let n = num_courses as usize;
+        let mut adjacency = vec![vec![]; n];
+        let mut entry = vec![0; n];
+        // init
+        for iter in prerequisites.iter() {
+            let (a, b) = (iter[0], iter[1]);
+            adjacency[b as usize].push(a);
+            entry[a as usize] += 1;
+        }
+        // construct deque & reslut
+        let mut deque = std::collections::VecDeque::new();
+        for index in 0..n {
+            if entry[index] == 0 {
+                deque.push_back(index);
+            }
+        }
+        let mut result = vec![];
+        // bfs
+        while !deque.is_empty() {
+            let head = deque.pop_front().unwrap();
+            result.push(head as i32);
+            // update degree of entry
+            for &out_entry in adjacency[head].iter() {
+                entry[out_entry as usize] -= 1;
+                if entry[out_entry as usize] == 0 {
+                    deque.push_back(out_entry as usize);
+                }
+            }
+        }
+        if result.len() == n {
+            result
+        } else {
+            vec![]
+        }
+    }
+}
+```
+
 ### **...**
 
 ```

solution/0200-0299/0210.Course Schedule II/README_EN.md

@@ -248,6 +248,49 @@ public class Solution {
 }
 ```
 
+### **Rust**
+
+```rust
+impl Solution {
+    pub fn find_order(num_courses: i32, prerequisites: Vec<Vec<i32>>) -> Vec<i32> {
+        let n = num_courses as usize;
+        let mut adjacency = vec![vec![]; n];
+        let mut entry = vec![0; n];
+        // init
+        for iter in prerequisites.iter() {
+            let (a, b) = (iter[0], iter[1]);
+            adjacency[b as usize].push(a);
+            entry[a as usize] += 1;
+        }
+        // construct deque & reslut
+        let mut deque = std::collections::VecDeque::new();
+        for index in 0..n {
+            if entry[index] == 0 {
+                deque.push_back(index);
+            }
+        }
+        let mut result = vec![];
+        // bfs
+        while !deque.is_empty() {
+            let head = deque.pop_front().unwrap();
+            result.push(head as i32);
+            // update degree of entry
+            for &out_entry in adjacency[head].iter() {
+                entry[out_entry as usize] -= 1;
+                if entry[out_entry as usize] == 0 {
+                    deque.push_back(out_entry as usize);
+                }
+            }
+        }
+        if result.len() == n {
+            result
+        } else {
+            vec![]
+        }
+    }
+}
+```
+
 ### **...**
 
 ```

solution/0200-0299/0210.Course Schedule II/Solution.rs

@@ -0,0 +1,38 @@
+impl Solution {
+    pub fn find_order(num_courses: i32, prerequisites: Vec<Vec<i32>>) -> Vec<i32> {
+        let n = num_courses as usize;
+        let mut adjacency = vec![vec![]; n];
+        let mut entry = vec![0; n];
+        // init
+        for iter in prerequisites.iter() {
+            let (a, b) = (iter[0], iter[1]);
+            adjacency[b as usize].push(a);
+            entry[a as usize] += 1;
+        }
+        // construct deque & reslut
+        let mut deque = std::collections::VecDeque::new();
+        for index in 0..n {
+            if entry[index] == 0 {
+                deque.push_back(index);
+            }
+        }
+        let mut result = vec![];
+        // bfs
+        while !deque.is_empty() {
+            let head = deque.pop_front().unwrap();
+            result.push(head as i32);
+            // update degree of entry
+            for &out_entry in adjacency[head].iter() {
+                entry[out_entry as usize] -= 1;
+                if entry[out_entry as usize] == 0 {
+                    deque.push_back(out_entry as usize);
+                }
+            }
+        }
+        if result.len() == n {
+            result
+        } else {
+            vec![]
+        }
+    }
+}