solve 14

Author: Zhang Xiaodong

src/solution/mod.rs

@@ -9,3 +9,4 @@ mod s0009_palindrome_number;
 mod s0011_container_with_most_water;
 mod s0012_integer_to_roman;
 mod s0013_roman_to_integer;
+mod s0014_longest_common_prefix;

src/solution/s0014_longest_common_prefix.rs

@@ -0,0 +1,70 @@
+/**
+ * [14] 最长公共前缀
+ *
+ * 编写一个函数来查找字符串数组中的最长公共前缀。
+ * 如果不存在公共前缀，返回空字符串 ""。
+ *  
+ * 示例 1：
+ *
+ * 输入：strs = ["flower","flow","flight"]
+ * 输出："fl"
+ *
+ * 示例 2：
+ *
+ * 输入：strs = ["dog","racecar","car"]
+ * 输出：""
+ * 解释：输入不存在公共前缀。
+ *  
+ * 提示：
+ *
+ * 	1 <= strs.length <= 200
+ * 	0 <= strs[i].length <= 200
+ * 	strs[i] 仅由小写英文字母组成
+ *
+ */
+pub struct Solution {}
+
+// problem: https://leetcode.cn/problems/longest-common-prefix/
+// discuss: https://leetcode.cn/problems/longest-common-prefix/discuss/?currentPage=1&orderBy=most_votes&query=
+
+// submission codes start here
+
+impl Solution {
+    pub fn longest_common_prefix(strs: Vec<String>) -> String {
+        let mut its: Vec<Box<dyn Iterator<Item = &u8>>> = strs[1..]
+            .iter()
+            .map(|s| Box::new(s.as_bytes().iter()) as Box<dyn Iterator<Item = &u8>>)
+            .collect();
+        let mut end = 0;
+        for c in strs[0].bytes() {
+            for it in &mut its {
+                let r = it.next();
+                if r.is_none() || *r.unwrap() != c {
+                    return String::from(&strs[0].as_str()[..end]);
+                }
+            }
+            end += 1;
+        }
+        strs[0].to_string()
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_14() {
+        Solution::longest_common_prefix(vec!["1".to_string()]);
+        assert_eq!(
+            Solution::longest_common_prefix(vec!["flower".to_string(), "flow".to_string(), "flight".to_string()]),
+            "fl"
+        );
+        assert_eq!(
+            Solution::longest_common_prefix(vec!["pig".to_string(), "sheep".to_string(), "flight".to_string()]),
+            ""
+        );
+    }
+}