Create 784-letter-case-permutation.rs

Author: memorycancel

784-letter-case-permutation.rs

@@ -0,0 +1,31 @@
+// 动态规划 回溯
+pub fn letter_case_permutation(s: String) -> Vec<String> {
+    let mut dp: Vec<String> = vec![String::new()];
+    let mut current_count = 1;
+    for c in s.chars().collect::<Vec<char>>() {
+        if c.is_numeric() {
+            for i in dp.len()-current_count..dp.len() {
+                let mut tmp = dp[i].clone();
+                tmp.push(c);
+                dp.push(tmp);
+            }
+        } else {
+            for i in dp.len()-current_count..dp.len() {
+                let mut tmp_lower = dp[i].clone();
+                let mut tmp_upper = dp[i].clone();
+                tmp_lower.push(c.to_ascii_lowercase());
+                tmp_upper.push(c.to_ascii_uppercase());
+                dp.push(tmp_lower);
+                dp.push(tmp_upper);
+            }
+        }
+        current_count *= 2;
+    }
+    dp.retain(|e|e.len() == s.len());
+    dp
+}
+
+fn main() {
+    let s = "a1b2".to_string();
+    println!("{:?}", letter_case_permutation(s));
+}