Reading comprehension
Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 3010 Accepted Submission(s): 1182
Problem Description
Read the program below carefully then answer the question.
#pragma comment(linker, "/STACK:1024000000,1024000000")
#include <cstdio>
#include<iostream>
#include <cstring>
#include <cmath>
#include <algorithm>
#include<vector>
const int MAX=100000*2;
const int INF=1e9;
int main()
{
int n,m,ans,i;
while(scanf("%d%d",&n,&m)!=EOF)
{
ans=0;
for(i=1;i<=n;i++)
{
if(i&1)ans=(ans*2+1)%m;
else ans=ans*2%m;
}
printf("%d\n",ans);
}
return 0;
}
Input
Multi test cases,each line will contain two integers n and m. Process to end of file.
[Technical Specification]
1<=n, m <= 1000000000
Output
For each case,output an integer,represents the output of above program.
Sample Input
1 10
3 100
Sample Output
1
5
Source
AC代码:
#include <set>
#include <cmath>
#include <queue>
#include <stack>
#include <vector>
#include <string>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <algorithm>
using namespace std;
typedef long long ll;
ll n,mod;
struct test
{
ll numbers[3][3];
test()
{
numbers[0][0] = 1, numbers[0][1] = 2, numbers[0][2] = 1;
numbers[1][0] = 1, numbers[1][1] = 0, numbers[1][2] = 0;
numbers[2][0] = 0, numbers[2][1] = 0, numbers[2][2] = 1;
}
};
test multiplying(test &AA,test &BB)
{
test r;
for(int i=0;i<3;i++)
{
for(int j=0;j<3;j++)
{
r.numbers[i][j]=0;
for(int k=0;k<3;k++)
{
r.numbers[i][j]=(r.numbers[i][j]+(AA.numbers[i][k]*BB.numbers[k][j])%mod)%mod;
}
}
}
return r;
}
void Pow(test A,ll n)
{
test B;
B.numbers[0][0]=2;
B.numbers[1][0]=1;
B.numbers[2][0]=1;
while(n>0)
{
if(n&1)B=multiplying(A,B);
A=multiplying(A,A);
n=n>>1;
}
cout << B.numbers[0][0]%mod << endl;
}
int main()
{
while(cin >> n >> mod)
{
if(n==1)
{
cout << 1%mod << endl; //和队友找了半天才发现,此处有坑!
continue ;
}
test A;
Pow(A,n-2);
}
}
细节决定成败!!!