Merge pull request #1527 from cezarbbb/Backtracking02

添加 0093.复原IP地址 Rust版本

problems/0093.复原IP地址.md

@@ -536,6 +536,53 @@ func isNormalIp(s string,startIndex,end int)bool{
 
 ```
 
+## Rust
+
+```Rust
+impl Solution {
+    fn is_valid(s: &Vec<char>, start: usize, end: usize) -> bool {
+        if start > end { return false; }
+        if s[start] == '0' && start != end { return false; }
+        let mut num = 0;
+        for i in start..=end {
+            if s[i] > '9' || s[i] < '0' { return false; }
+            if let Some(digit) = s[i].to_digit(10) { num = num * 10 + digit; }
+            if num > 255 { return false; }
+        }
+        true
+    }
+
+    fn backtracking(result: &mut Vec<String>, s: &mut Vec<char>, start_index: usize, mut point_num: usize) {
+        let len = s.len();
+        if point_num == 3 {
+            if Self::is_valid(s, start_index, len - 1) {
+                result.push(s.iter().collect::<String>());
+            }
+            return;
+        }
+        for i in start_index..len {
+            if Self::is_valid(s, start_index, i) {
+                point_num += 1;
+                s.insert(i + 1, '.');
+                Self::backtracking(result, s, i + 2, point_num);
+                point_num -= 1;
+                s.remove(i + 1);
+            }   else { break; }
+        }
+    }
+
+    pub fn restore_ip_addresses(s: String) -> Vec<String> {
+        let mut result: Vec<String> = Vec::new();
+        let len = s.len();
+        if len < 4 || len > 12 { return result; }
+        let mut s = s.chars().collect::<Vec<char>>();
+        Self::backtracking(&mut result, &mut s, 0, 0);
+        result
+    }
+
+}
+```
+
 ## C 
 ```c
 //记录结果