LeetCode-14 Longest Common Prefix.cpp

class Solution {
public:
    string longestCommonPrefix(vector<string>& strs) {
        
        //edge case, empty array
        if(strs.empty()) return "";
        
        //empty string
        string ans;
        
        //200 is the max possible length of string, as per constraints
        int minLen = 200;
        
        //finding minLen
        for(string s : strs)
            minLen = min(minLen, (int)s.length());
        
        //checking characters from index 0 to minLen-1
        for(int i=0; i<minLen; i++)
        {
            //character at index i of first string 
            char ch = strs[0][i];
            
            //looping throgh all the strings
            for(int j=0; j<strs.size(); j++)
            {
                //the character differs
                if(strs[j][i] != ch)
                {
                    //ans cannot be expanded further
                    return ans;
                }
            }
            
            //ch is same across all strings, expand our answer
            ans.push_back(ch);
        }
        
        return ans;
    }
};