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CROCH_rollinghash.cpp
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CROCH_rollinghash.cpp
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/*
* J1K7_7
*
* You can use my contents on a Creative Commons - Attribution 4.0 International - CC BY 4.0 License. XD
* - JASKAMAL KAINTH
*/
#include <iostream>
#include <sstream>
#include <fstream>
#include <string>
#include <vector>
#include <deque>
#include <queue>
#include <stack>
#include <set>
#include <cstring>
#include <cassert>
#include <list>
#include <map>
#include <unordered_map>
#include <iomanip>
#include <algorithm>
#include <functional>
#include <utility>
#include <bitset>
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <cstdio>
#include <limits>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef vector<long long> vll;
#define left(x) (x << 1)
#define right(x) (x << 1) + 1
#define mid(l, r) ((l + r) >> 1)
#define mp make_pair
#define pb push_back
#define all(a) a.begin(),a.end()
#define debug(x) {cerr <<#x<<" = " <<x<<"\n"; }
#define debug2(x, y) {cerr <<#x<<" = " <<x<<", "<<#y <<" = " <<y <<"\n";}
#define debug3(x, y, z) {cerr <<#x<<" = " <<x<<", "<<#y <<" = " <<y <<", "<<#z<<" = "<<z<<"\n";}
#define debug4(x, y, z, w) {cerr <<#x<<" = " <<x<<", "<<#y <<" = " <<y <<", "<<#z<<" = "<<z<<", "<<#w << " = " <<w <<"\n";}
#define ss second
#define ff first
#define m0(x) memset(x,0,sizeof(x))
const int mod=1e9+7;
template<class T> inline T gcd(T a,T b){ll t;while(b){a=a%b;t=a;a=b;b=t;}return a;}
template<class T> inline T lcm(T a,T b){return a/gcd(a,b)*b;}
template<typename T, typename S> T expo(T b, S e, const T &m){if(e <= 1)return e == 0?1: b;\
return (e&1) == 0?expo((b*b)%m, e>>1, m): (b*expo((b*b)%m, e>>1, m))%m;}
template<typename T> T modinv(T a) { return expo(a, mod-2, mod); }
inline int nextint(){ int x; scanf("%d",&x); return x; }
inline ll nextll(){ ll x; scanf("%lld",&x); return x; }
const ll mx_ll = numeric_limits<ll> :: max();
const int mx_int = numeric_limits<int> :: max();
const long double PI = (long double)(3.1415926535897932384626433832795);
const int MAXN = 5e3+7;
string s;
int len;
int P[MAXN], HashF[MAXN], HashR[MAXN];
class RollingHash {
public:
RollingHash() {
prime = 100001;
mod1 = 1000000007;
mod2 = 1897266401;
P[0] = 1;
for(int i=1; i<MAXN; i++) {
P[i] = 1LL * P[i-1] * prime % mod1;
}
}
void Construct() {
HashF[0] = HashR[ len+1 ] = 0;
for(int i=1; i<=len; i++) {
HashF[i] = ( 1LL * HashF[i-1] * prime + s[i-1] ) % mod1;
HashR[len-i+1] = ( 1LL * HashR[len-i+2] * prime + s[ len - i ] ) % mod1;
}
}
int GetForwardHash( int l, int r ) {
if( l == 1 ) return HashF[r];
int hash = HashF[r] - 1LL * HashF[l-1] * P[ r - l + 1 ] % mod1;
if( hash < 0 ) hash += mod1;
return hash;
}
int GetBackwardHash( int l, int r ) {
if( r == len ) return HashR[l];
int hash = HashR[l] - 1LL * HashR[r+1] * P[ r - l + 1 ] % mod1;
if( hash < 0 ) hash += mod1;
return hash;
}
bool IsPalin( int l, int r ) {
if( r < l ) return true;
return (GetForwardHash(l, r) == GetBackwardHash(l, r));
}
private:
int prime, mod1, mod2;
};
int dp[MAXN][MAXN];
int main()
{
ios_base::sync_with_stdio(false); cin.tie(0);
cin >> s;
len = s.length();
RollingHash obj;
obj.Construct();
for(int i = 0; i < len; i++)
dp[i][i] = 1;
for(int l = 1; l <= len; l++)
{
for(int st = 0; st < len; st++)
{
int en = st+l-1;
if(en > len)
break;
dp[st][en] = dp[st][en-1] + dp[st+1][en] - dp[st+1][en-1] + obj.IsPalin(st+1,en+1);
}
}
int q; cin >> q;
while(q--)
{
int l ,r; cin >> l >> r;
l--,r--;
cout << dp[l][r] << "\n";
}
return 0;
}