Submission #491020

#	Time	Username	Problem	Language	Result	Execution time	Memory
491020		kawaii	Fibonacci representations (CEOI18_fib)	C++14	0 / 100	14 ms	8140 KiB

fib

#include <bits/stdc++.h>
using namespace std; 

#define int long long
#define hash hashh

int t, hash[1000005], mod = 998244353, base = 353, mul[1000005];
string s;

void solve(){  
    mul[0] = 1;
    for(int i = 1; i <= 1e6; i++) mul[i] = (mul[i - 1] * base) % mod;
    while(t--){
        cin >> s; 
        int ans = 0, n = s.size();
        for(int i = 0; i < s.size(); i++) hash[i + 1] = (hash[i] * base + s[i]) % mod;  
        int l = 1, r = n, cnt = n;
        while(l <= r){
            int p = (hash[cnt] - hash[r - 1] * mul[cnt - r + 1]) % mod;
            if(p < 0) p += mod;
            int q = (hash[l + cnt - r] - hash[l - 1] * mul[cnt - r + 1]) % mod;
            if(q < 0) q += mod; 
            if(p == q){
                ans += 2;
                if(l == r) ans--;
                l += cnt - r + 1;
                cnt = r - 1;
            }
            r--;
        }
        cout << ans << "\n";
    }
}
 
signed main(){  
    ios_base::sync_with_stdio(NULL); cin.tie(nullptr); cout.tie(nullptr);
    cin >> t;
    solve();
}

Compilation message (stderr)

fib.cpp: In function 'void solve()':
fib.cpp:16:26: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   16 |         for(int i = 0; i < s.size(); i++) hash[i + 1] = (hash[i] * base + s[i]) % mod;
      |                        ~~^~~~~~~~~~

• Subtask 1: 0 / 5
• Subtask 2: 0 / 20
• Subtask 3: 0 / 15
• Subtask 4: 0 / 10
• Subtask 5: 0 / 15
• Subtask 6: 0 / 35