Submission #409319

#	Time	Username	Problem	Language	Result	Execution time	Memory
409319		Hazem	Palindromic Partitions (CEOI17_palindromic)	C++14	100 / 100	347 ms	18432 KiB

palindromic

#include <bits/stdc++.h>
using namespace std;
 
#define LL long long
#define F first
#define S second
#define pii pair<int,int>
#define piii pair<pair<int,int>,int>

const int N = 1e6+10;
const int M = 101;
const LL INF = 1e9;
const LL LINF = 2e18;
const LL MOD = 1e9+7;
const double PI = 3.141592653589793;

string s;
int chash[N];
int powers[N];

int add(LL a,LL b){
    return (a+b)%MOD;
}

int mult(LL a,LL b){
    return (a*b)%MOD;
}


bool check(int l1,int r1,int l2,int r2){

    LL h1 = ((chash[r2]-chash[l2-1])%MOD+MOD)%MOD;
    LL h2 = ((chash[r1]-(l1?chash[l1-1]:0))%MOD+MOD)%MOD;
    h2 = mult(h2,powers[l2-l1]);

    return h1==h2;
}

int solve(int l,int r){

    if(l>r)
        return 0;

    for(int i=l;i<(l+r+1)/2;i++)
        if(check(l,i,r-(i-l),r))
            return 2+solve(i+1,r-(i-l)-1);

    return 1;
}

int main(){

    //freopen("out.txt","w",stdout);
    powers[0] = 1;
    for(int i=1;i<=1e6;i++)
        powers[i] = mult(powers[i-1],31);

    int t;
    scanf("%d",&t);

    while(t--){

        cin>>s;
        int n  = s.size();
    
        for(int i=0;i<n;i++)
            chash[i] = add(i?chash[i-1]:0,mult(s[i]-'a'+1,powers[i]));

        printf("%d\n",solve(0,n-1));     
    }
}   

Compilation message (stderr)

palindromic.cpp: In function 'int main()':
palindromic.cpp:59:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   59 |     scanf("%d",&t);
      |     ~~~~~^~~~~~~~~

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