hdu 5459 Jesus Is Here （费波纳茨递推）

I‘ve sent Fang Fang around 201314 text messages in almost 5 years. Why can‘t she make sense of what I mean?
``But Jesus is here!" the priest intoned. ``Show me your messages."
Fine, the first message is s1=‘‘c" and the second one is s2=‘‘ff".
The i-th message is si=si−2+si−1 afterwards. Let me give you some examples.
s3=‘‘cff", s4=‘‘ffcff" and s5=‘‘cffffcff".

``I found the i-th message‘s utterly charming," Jesus said.
``Look at the fifth message". s5=‘‘cffffcff" and two ‘‘cff" appear in it.
The distance between the first ‘‘cff" and the second one we said, is 5.
``You are right, my friend," Jesus said. ``Love is patient, love is kind.
It does not envy, it does not boast, it is not proud. It does not dishonor others, it is not self-seeking, it is not easily angered, it keeps no record of wrongs.
Love does not delight in evil but rejoices with the truth.
It always protects, always trusts, always hopes, always perseveres."

Listen - look at him in the eye. I will find you, and count the sum of distance between each two different ‘‘cff" as substrings of the message.

An integer T (1≤T≤100), indicating there are T test cases.
Following T lines, each line contain an integer n (3≤n≤201314), as the identifier of message.

The output contains exactly T lines.
Each line contains an integer equaling to:

where sn as a string corresponding to the n-th message.

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

const int N = 201413;
const int M = 530600414;
typedef long long ll;

ll dp[N], rd[N], ld[N];
ll ls[N], cnt[N];

void init()
{
    ls[3] = 3; cnt[3] = 1; dp[3] = 0;
    ls[4] = 5; cnt[4] = 1; dp[4] = 0;
    rd[3] = 3; ld[3] = 0;
    rd[4] = 3; ld[4] = 2;
    for(int i = 5; i < N; ++i)
    {
        ls[i] = (ls[i - 1] + ls[i - 2]) % M;
        cnt[i] = (cnt[i - 1] + cnt[i - 2]) % M;

        rd[i] = (rd[i - 2] + rd[i - 1] + cnt[i - 2] * ls[i - 1]) % M;
        ld[i] = (ld[i - 2] + ld[i - 1] + cnt[i - 1] * ls[i - 2]) % M;

        dp[i] = (dp[i - 1] + dp[i - 2] + cnt[i - 1] * rd[i - 2] + cnt[i - 2] * ld[i - 1]) % M;
    }
}

int main()
{
    int _, cas = 1; scanf("%d", &_);
    init();
    while(_ --)
    {
        int n; scanf("%d", &n);
        printf("Case #%d: %lld\n",cas++, dp[n] % M);
    }
    return 0;
}

I‘ve sent Fang Fang around 201314 text messages in almost 5 years. Why can‘t she make sense of what I mean?
``But Jesus is here!" the priest intoned. ``Show me your messages."
Fine, the first message is s1=‘‘c" and the second one is s2=‘‘ff".
The i-th message is si=si−2+si−1 afterwards. Let me give you some examples.
s3=‘‘cff", s4=‘‘ffcff" and s5=‘‘cffffcff".

``I found the i-th message‘s utterly charming," Jesus said.
``Look at the fifth message". s5=‘‘cffffcff" and two ‘‘cff" appear in it.
The distance between the first ‘‘cff" and the second one we said, is 5.
``You are right, my friend," Jesus said. ``Love is patient, love is kind.
It does not envy, it does not boast, it is not proud. It does not dishonor others, it is not self-seeking, it is not easily angered, it keeps no record of wrongs.
Love does not delight in evil but rejoices with the truth.
It always protects, always trusts, always hopes, always perseveres."

Listen - look at him in the eye. I will find you, and count the sum of distance between each two different ‘‘cff" as substrings of the message.

An integer T (1≤T≤100), indicating there are T test cases.
Following T lines, each line contain an integer n (3≤n≤201314), as the identifier of message.

The output contains exactly T lines.
Each line contains an integer equaling to:

where sn as a string corresponding to the n-th message.