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Copy pathZAlgo.cpp
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46 lines (43 loc) · 1 KB
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Copy pathZAlgo.cpp
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46 lines (43 loc) · 1 KB
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//author @Nishant
#include<bits/stdc++.h>
using namespace std;
void zAlgo(string txt, string pat){
string mergerd = pat + '$' + txt;
int n = mergerd.size();
//cout << mergerd;
int Z[n];
int R = 0, L = 0;
for(int i=1; i<n; i++){
if (i > R){
L = R = i;
while (R < n && mergerd.at(R-L) == mergerd.at(R)){
R++;
}
Z[i] = R-L;
R--;
}else{
int k = i-L;
if(Z[k] < R-i+1){
Z[i] = Z[k];
}else{
L = i;
while (R < n && mergerd.at(R-L) == mergerd.at(R)){
R++;
}
Z[i] = R-L;
R--;
}
}
}
for (int i = 0; i < n; ++i)
{
if (Z[i] == pat.size())
cout << "Found pattern at index " << i - pat.size() -1 << endl;
}
}
int main(){
string txt, pat;
getline(cin, txt);
getline(cin, pat);
zAlgo(txt, pat);
}