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: ""
Explanation: There is no common prefix among the input strings.
Note:
All given inputs are in lowercase letters a-z.
Solution:
Iterate through index, check every string against the first string.
class Solution {
public:
string longestCommonPrefix(vector<string>& strs) {
int i=0;
if(strs.empty()) return "";
while(true){
char c;
for(int j=0;j<strs.size();j++){
if(i>=strs[j].size()){
return strs[0].substr(0,i);
}
if(j==0) c=strs[j][i];
else{
if(strs[j][i]!=c) return strs[0].substr(0,i);
}
}
i++;
}
return strs[0].substr(0,i);
}
};