HDU 2817（等差和等比数列问题）

A sequence of numbers

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 529    Accepted Submission(s): 162

Problem Description

Xinlv wrote some sequences on the paper a long time ago, they might be arithmetic or geometric sequences. The numbers are not very clear now, and only the first three numbers of each sequence are recognizable. Xinlv wants to know some numbers in these sequences, and he needs your help.

 

 

Input

The first line contains an integer N, indicting that there are N sequences. Each of the following N lines contain four integers. The first three indicating the first three numbers of the sequence, and the last one is K, indicating that we want to know the K-th numbers of the sequence.

You can assume 0 < K <= 10^9, and the other three numbers are in the range [0, 2^63). All the numbers of the sequences are integers. And the sequences are non-decreasing.

 

 

Output

Output one line for each test case, that is, the K-th number module (%) 200907.

 

 

Sample Input

  

   2
1 2 3 5
1 2 4 5
  

 

 

Sample Output

  

   5
16
  

 

 

Source

2009 Multi-University Training Contest 1 - Host by TJU

 

 

Recommend

gaojie

此题主要注意的是不要溢出，重点在等比数列的计算

#include <stdio.h> #define m 200907 __int64 div(__int64 q,__int64 n) { __int64 sum=1; while(n) { if(n&1) { sum*=q;sum%=m; } q=(q*q)%m; n/=2; } return sum; } int main() { int n; __int64 a1,a2,a3,k,s; scanf("%d",&n); while(n--) { scanf("%I64d%I64d%I64d%I64d",&a1,&a2,&a3,&k); int flag; if(a3-a2==a2-a1) flag=1; // 等差 else flag=2; //等比 if(flag==1) { __int64 d=a2-a1; a1%=m;d%=m;k%=m; s=(a1+(k-1)*d)%m; } else { __int64 q=a2/a1; a1%=m; s=(a1*div(q,k-1))%m; } printf("%I64d/n",s); } return 0; }