20240705 Finished

src/problem/mod.rs

@@ -167,3 +167,4 @@ mod p211_design_add_and_search_words_data_structure;
 mod p212_word_search_ii;
 mod p17_letter_combinations_of_a_phone_number;
 mod p77_combinations;
+mod p46_permutations;

src/problem/p46_permutations.rs

@@ -0,0 +1,49 @@
+/**
+ * [46] Permutations
+ */
+pub struct Solution {}
+
+
+// submission codes start here
+
+impl Solution {
+    pub fn permute(nums: Vec<i32>) -> Vec<Vec<i32>> {
+        let mut result = vec![];
+        let mut output = nums.clone();
+
+        Self::search(output.len(), &mut output, &mut result, 0);
+
+        result
+    }
+
+    fn search(length: usize, output: &mut Vec<i32>, result: &mut Vec<Vec<i32>>, pos: usize) {
+        if length == pos {
+            result.push(output.clone());
+            return;
+        }
+        
+        for i in pos..length {
+            Self::swap(output, i, pos);
+            Self::search(length, output, result, pos + 1);
+            Self::swap(output, i, pos);
+        }
+        
+    }
+    
+    fn swap(output: &mut Vec<i32>, a: usize, b: usize) {
+        let temp = output[a];
+        output[a] = output[b];
+        output[b] = temp;
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_46() {
+    }
+}