Submission #131850

#	Time	Username	Problem	Language	Result	Execution time	Memory
131850		Vardanyan	Palindromic Partitions (CEOI17_palindromic)	C++14	100 / 100	90 ms	26872 KiB

palindromic

#include <bits/stdc++.h>
using namespace std;
string st;
const int N = 1000*1000+5;
long long pw[N];
long long hsh[N];
long long gethash(int l,int r){
    return hsh[r]-hsh[l-1]*pw[r-l+1];
}
int solve(int s,int e,int l, int r){
    if(l>r) return 0;
    if(s == l && e == r && l == r) return 1;

    //string s1,s2;
  //  for(int i = s;i<=l;i++) s1+=st[i];
  //  for(int i = r;i<=e;i++) s2+=st[i];
    long long s1 = gethash(s+1,l+1);
    long long s2 = gethash(r+1,e+1);
    if(s1 == s2){

       return 2+solve(l+1,r-1,l+1,r-1);
    }
    else{
        if(r-l == 1) return 1;
        if(r-l == 2) return 1;
        return solve(s,e,l+1,r-1);
    }
}
int main(){
    ios_base::sync_with_stdio(false);
    int t;
    cin>>t;
    pw[0] = 1;
    for(int i = 1;i<=1000*1000;i++) pw[i] = pw[i-1]*259;
    while(t--){
        cin>>st;
    for(int i = 1;i<=st.length();i++) hsh[i]=(hsh[i-1]*259+(st[i-1]));
        cout<<solve(0,st.length()-1,0,st.length()-1)<<endl;
    }
    return 0;
}

Compilation message (stderr)

palindromic.cpp: In function 'int main()':
palindromic.cpp:37:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 1;i<=st.length();i++) hsh[i]=(hsh[i-1]*259+(st[i-1]));
                   ~^~~~~~~~~~~~~

• Subtask 1: 15 / 15
• Subtask 2: 20 / 20
• Subtask 3: 25 / 25
• Subtask 4: 40 / 40