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