62 lines
1.5 KiB
C++
62 lines
1.5 KiB
C++
/*
|
|
Description: Given two strings, return the longest common prefix from both of the strings.
|
|
Longest common prefix means returning the starting characters which are common in both the strings.
|
|
For e.g.,
|
|
s1 = "hello"
|
|
s2 ="heat"
|
|
Longest common prefix will be "he"
|
|
Because only two characters from the starting are common between them.
|
|
|
|
Time Complexity: O(n) where n is the length of the string
|
|
*/
|
|
#include <iostream>
|
|
using namespace std;
|
|
|
|
//function starts
|
|
string lcp(string s1, string s2)
|
|
{
|
|
string ans = "";
|
|
if (s1.size() == 0 || s2.size() == 0)
|
|
{
|
|
return ans;
|
|
}
|
|
//in 'm' variable, we are storing the smallest string's size from s1 and s2
|
|
//because the prefix will always be at most the size of the smallest string
|
|
int m = s1.size() < s2.size() ? s1.size() : s2.size();
|
|
for (int i = 0; i < m; i++)
|
|
{
|
|
//if both the starting characters are not same, then break from the for loop
|
|
if (s1[i] != s2[i])
|
|
{
|
|
break;
|
|
}
|
|
//else if they are same, add the character in the answer string
|
|
else
|
|
{
|
|
ans += s1[i];
|
|
}
|
|
}
|
|
return ans;
|
|
}
|
|
|
|
//main starts
|
|
int main()
|
|
{
|
|
string s1;
|
|
string s2;
|
|
cout << "Enter string-1 : \n";
|
|
getline(cin, s1);
|
|
cout << "Enter string-2: \n";
|
|
getline(cin, s2);
|
|
cout << "Longest common prefix is: " << lcp(s1, s2);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
Sample Input:
|
|
string s1 = "flower"
|
|
string s2 = "flight"
|
|
|
|
Output
|
|
Longest common prefix is: fl
|
|
*/ |