LeetCode Problem No.14.
No.13 is here.
14. Longest Common Prefix
Write a function to find the longest common prefix string amongst an array of strings. If there is no common prefix, return an empty string "".
Example 1
Input: strs = ["flower","flow","flight"] Output: "fl"
Example 2
Input: strs = ["dog","racecar","car"] Output: "" Explanation: There is no common prefix among the input strings.
Constraints
1 <= strs.length <= 200 0 <= strs[i].length <= 200 strs[i] consists of only lower-case English letters.
Code
object Solution { def longestCommonPrefix(strs: Array[String]): String = { def run(targets:Array[String], acc:String): String = { if(!targets.head.isEmpty && targets.tail.forall{ x => !x.isEmpty && x.head == targets.head.head }) run(targets.map(_.tail), acc+targets.head.head) else acc } run(strs, "") } }
Methods
Compare n-th character in each strs.
- All n-th character are same, accumulate n-th character and increment n.
- All n-th character are not same, return accumulated characters.
Results
Runtime: 679 ms, faster than 72.08% of Scala online submissions for Longest Common Prefix. Memory Usage: 71.8 MB, less than 11.69% of Scala online submissions for Longest Common Prefix.
