Print Longest Common Substring

/* You are given two string. Find the Largest Common Substring (not Subsequence). First, insert all the suffix (suffix of "suffix" are "x", "ix"......"suffix") of the first string in the "Trie", then check with the all the second-string-suffix's. */ #include<bits/stdc++.h> using namespace std; int cnt=1, ans=0, st=0; string s, ss; struct node{ int next[26+1]; }ar[10000]; void new_trie(int cur){ for(int i=0; i<=26; i++) ar[cur].next[i]=-1; } void insert(){ // Inserting the first string int sz=s.size(), cur=0, x; for(int i=0; i<sz; i++){ x=s[i]-'a'; if(ar[cur].next[x]==-1){ ar[cur].next[x]=cnt; new_trie(cnt++); } cur=ar[cur].next[x]; } } void find(int stt){ // Checking with the second string int sz=s.size(), cur=0, x, c=0; for(int i=0; i<sz; i++){ x=s[i]-'a'; if(ar[cur].next[x]==-1) break; cur=ar[cur].next[x]; c++; } if(c>ans){ // when larger counter(c) is found st=stt; ans=c; } } int main(){ int sz; new_trie(0); cin>>ss; // First String sz=ss.size(); for(int i=1; i<=sz; i++){ s=""; for(int ii=sz-i; ii<sz; ii++) s+=ss[ii]; insert(); } cin>>ss; // Second String sz=ss.size(); for(int i=1; i<=sz; i++){ s=""; for(int ii=sz-i; ii<sz; ii++) s=s+ss[ii]; find(sz-i); } for(int i=st, cc=1; cc<=ans; i++, cc++) cout<<ss[i]; return 0; }