javascript - Javascript 中最长的公共(public)前缀

Question

我正在尝试解决 Leet Code 挑战 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.

我的解决方案:

let strs = ["flower", "flow", "flight"];

var longestCommonPrefix = function (strs) {
  for (let i = 0; i < strs.length; i++) {
    for (let j = 0; j < strs[i].length; j++) {
       // console.log(strs[i+2][j]);
      if (strs[i][j] == strs[i + 1][j] && strs[i + 1][j] ==strs[i + 2][j]) {
        return (strs[i][j]);
        
      } else {
        return "0";
      }
    }
  }
};

console.log(longestCommonPrefix(strs));

输出: f如何遍历每个字符并检查它是否相同，然后继续下一步，如果失败，则将返回最长的公共(public)前缀？

Answer 1

由于最长的公共(public)前缀必须出现在数组的每个字符串中，您可以迭代长度并检查所有单词在该索引处是否具有相同的字符，直到找到差异

function prefix(words){
  // check border cases size 1 array and empty first word)
  if (!words[0] || words.length ==  1) return words[0] || "";
  let i = 0;
  // while all words have the same character at position i, increment i
  while(words[0][i] && words.every(w => w[i] === words[0][i]))
    i++;
  
  // prefix is the substring from the beginning to the last successfully checked i
  return words[0].substr(0, i);
}

console.log(1, prefix([]));
console.log(2, prefix([""]));
console.log(3, prefix(["abc"]));
console.log(4, prefix(["abcdefgh", "abcde", "abe"]));
console.log(5, prefix(["abc", "abc", "abc"]));
console.log(6, prefix(["abc", "abcde", "xyz"]));