添加 0017.电话号码的字母组合 0077.组合 0077.组合优化 0216.组合总和III Rust版本

添加 0017.电话号码的字母组合 0077.组合 0077.组合优化 0216.组合总和III Rust版本

problems/0017.电话号码的字母组合.md

@@ -454,6 +454,49 @@ function letterCombinations(digits: string): string[] {
 };
 ```
 
+## Rust
+
+```Rust
+impl Solution {
+    fn backtracking(result: &mut Vec<String>, s: &mut String, map: &[&str; 10], digits: &String, index: usize)  {
+        let len = digits.len();
+        if len == index {
+            result.push(s.to_string());
+            return;
+        }
+        // 在保证不会越界的情况下使用unwrap()将Some()中的值提取出来
+        let digit= digits.chars().nth(index).unwrap().to_digit(10).unwrap() as usize;
+        let letters = map[digit];
+        for i in letters.chars() {
+            s.push(i);
+            Self::backtracking(result, s, &map, &digits, index+1);
+            s.pop();
+        }
+    }
+    pub fn letter_combinations(digits: String) -> Vec<String> {
+        if digits.len() == 0 {
+            return vec![];
+        }
+        const MAP: [&str; 10] = [
+        "",
+        "",
+        "abc",
+        "def",
+        "ghi",
+        "jkl",
+        "mno",
+        "pqrs",
+        "tuv",
+        "wxyz"
+        ];
+        let mut result: Vec<String> = Vec::new();
+        let mut s: String = String::new();
+        Self::backtracking(&mut result, &mut s, &MAP, &digits, 0);
+        result
+    }
+}
+```
+
 ## C
 
 ```c

problems/0077.组合.md

@@ -535,6 +535,56 @@ func backtrack(n,k,start int,track []int){
 }
 ```
 
+### Rust
+
+```Rust
+impl Solution {
+    fn backtracking(result: &mut Vec<Vec<i32>>, path: &mut Vec<i32>, n: i32, k: i32, startIndex: i32) {
+        let len= path.len() as i32;
+        if len == k{
+            result.push(path.to_vec());
+            return;
+        }
+        for i in startIndex..= n {
+            path.push(i);
+            Self::backtracking(result, path, n, k, i+1);
+            path.pop();
+        }
+    }
+    pub fn combine(n: i32, k: i32) -> Vec<Vec<i32>> {
+        let mut result: Vec<Vec<i32>> = Vec::new();
+        let mut path: Vec<i32> = Vec::new();
+        Self::backtracking(&mut result, &mut path, n, k, 1);
+        result
+    }
+}
+```
+
+剪枝
+```Rust
+impl Solution {
+    fn backtracking(result: &mut Vec<Vec<i32>>, path: &mut Vec<i32>, n: i32, k: i32, startIndex: i32) {
+        let len= path.len() as i32;
+        if len == k{
+            result.push(path.to_vec());
+            return;
+        }
+	// 此处剪枝
+        for i in startIndex..= n - (k - len) + 1 {
+            path.push(i);
+            Self::backtracking(result, path, n, k, i+1);
+            path.pop();
+        }
+    }
+    pub fn combine(n: i32, k: i32) -> Vec<Vec<i32>> {
+        let mut result: Vec<Vec<i32>> = Vec::new();
+        let mut path: Vec<i32> = Vec::new();
+        Self::backtracking(&mut result, &mut path, n, k, 1);
+        result
+    }
+}
+```
+
 ### C
 ```c
 int* path;

problems/0077.组合优化.md

@@ -261,6 +261,32 @@ function combine(n: number, k: number): number[][] {
 };
 ```
 
+Rust:
+
+```Rust
+impl Solution {
+    fn backtracking(result: &mut Vec<Vec<i32>>, path: &mut Vec<i32>, n: i32, k: i32, startIndex: i32) {
+        let len= path.len() as i32;
+        if len == k{
+            result.push(path.to_vec());
+            return;
+        }
+	// 此处剪枝
+        for i in startIndex..= n - (k - len) + 1 {
+            path.push(i);
+            Self::backtracking(result, path, n, k, i+1);
+            path.pop();
+        }
+    }
+    pub fn combine(n: i32, k: i32) -> Vec<Vec<i32>> {
+        let mut result: Vec<Vec<i32>> = Vec::new();
+        let mut path: Vec<i32> = Vec::new();
+        Self::backtracking(&mut result, &mut path, n, k, 1);
+        result
+    }
+}
+```
+
 C:
 
 ```c

problems/0216.组合总和III.md

@@ -411,6 +411,35 @@ function combinationSum3(k: number, n: number): number[][] {
 };
 ```
 
+## Rust
+
+```Rust
+impl Solution {
+    fn backtracking(result: &mut Vec<Vec<i32>>, path:&mut Vec<i32>, targetSum:i32, k: i32, mut sum: i32, startIndex: i32) {
+        let len = path.len() as i32;
+        if len == k {
+            if sum == targetSum {
+                result.push(path.to_vec());
+            }
+            return;
+        }
+        for i in startIndex..=9 {
+            sum += i;
+            path.push(i);
+            Self::backtracking(result, path, targetSum, k, sum, i+1);
+            sum -= i;
+            path.pop();
+        }
+    }
+    pub fn combination_sum3(k: i32, n: i32) -> Vec<Vec<i32>> {
+        let mut result: Vec<Vec<i32>> = Vec::new();
+        let mut path: Vec<i32> = Vec::new();
+        Self::backtracking(&mut result, &mut path, n, k, 0, 1);
+        result
+    }
+}
+```
+
 ## C
 
 ```c