LeetCode 實作解說系列-Longest Common Prefix

題目解說

原題目

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:

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Input: strs = ["flower","flow","flight"]
Output: "fl"

Example 2:

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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 lowercase English letters.

翻譯

給定一個陣列strs，裡面會有字串，找出此陣列字串相同的前綴，如果沒有，返回""。

解題策略

邏輯上是後面的字串去跟前面的做比較就好，所以聲明字串pre，一開始就宣告為陣列的第一個元素，如果比對不到，就將pre刪掉一個字符，刪到比對出相同前綴為止。

JS程式碼

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var longestCommonPrefix = function(strs) {
   if(strs == null || strs.length == 0) return "";
   let pre =strs[0]
   console.log(strs.length)
   for(let i =1;i<strs.length;i++){
       while(strs[i].indexOf(pre) != 0){
           pre=pre.substring(0, pre.length - 1);
       }
   }
    return pre;
};