49 lines
1.3 KiB
C++
49 lines
1.3 KiB
C++
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//Given two strings ‘s1’ and ‘s2’, find the length of the longest common substring.
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//NOTE: A substring is a contiguous part of string.
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// Input : X = “abcdxyz”, y = “xyzabcd”
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// Output : 4
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// Explanation: The longest common substring is “abcd” and is of length 4.
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//Program using Dynamic Programming
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//TIME COMPLEXITY: O(m*n)
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#include <iostream>
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using namespace std;
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int longestCommonSubstring(string s1,string s2,int n,int m)
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{
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int ans=0;
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int T[n+1][m+1];
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for(int i=0;i<=n;i++)
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{
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for(int j=0;j<=m;j++)
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{
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if(i==0 || j==0) // if length of any of the string is 0 then the length of longest common substring will be 0
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T[i][j]=0;
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else
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if(s1[i-1]==s2[j-1]) // if characters are equal, add 1 and update the answer according to maximum length
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{
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T[i][j]=1+T[i-1][j-1];
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ans=max(ans,T[i][j]);
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}
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else//if characters are not equal, make the current value in the array as 0
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T[i][j]=0;
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}
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}
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return ans;
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}
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int main()
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{
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string s1,s2;
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cout<<"Enter 1st string: "<<endl;
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cin>>s1;
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cout<<"Enter 2nd string: "<<endl;
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cin>>s2;
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int n=s1.length();
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int m=s2.length();
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cout<<"Length of longest common substring: "<<longestCommonSubstring(s1,s2,n,m);
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return 0;
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}
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// s1: abcde
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// s2:abfce
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// output: 2(ab)
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