[leetcode]LeetCode刷题的日子--longest common prefix

题目

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: ["flower","flow","flight"]
Output: "fl"

Example 2:

Input: ["dog","racecar","car"]
Output: ""

解题思路

是一道简单题，基本思路就是先找到最小需要比较的位数，确定循环边界，然后依次比对就可以了

代码

fn longest_common_prefix(strs: Vec<String>) -> String {
    if strs.len() == 0 {
        return String::from("");
    }

    if strs.len() == 1 {
        return strs[0].to_string();
    }

    let min_len = strs.iter().map(|s| s.len()).min().unwrap();

    for i in 0..min_len {
        let c = strs[0].chars().nth(i).unwrap();

        for s in &strs {
            if s.chars().nth(i).unwrap() != c {
                return s[0..i].to_string();
            }
        }
    }

    return strs[0][..min_len].to_string();
}

#[test]
fn test_logest_common_prefix() {
    let demo = vec![String::from("flower"), String::from("flow"), String::from("flight")];
    assert_eq!(longest_common_prefix(demo), "fl");
}