【單調隊列】HDU_3706_Second My Problem First

Second My Problem First

Time Limit: 12000/4000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)
Total Submission(s): 1931    Accepted Submission(s): 734

Problem Description

Give you three integers n, A and B.
Then we define S_i = Aⁱ mod B and T_i = Min{ S_k | i-A <= k <= i, k >= 1}
Your task is to calculate the product of T_i (1 <= i <= n) mod B.

 

Input

Each line will contain three integers n(1 <= n <= 10⁷),A and B(1 <= A, B <= 2³¹-1).
Process to end of file.

 

Output

For each case, output the answer in a single line.

 

Sample Input

1 2 3 2 3 4 3 4 5 4 5 6 5 6 7

 

Sample Output

2 3 4 5 6

 

Author

WhereIsHeroFrom@HDU

 

Source

HDOJ 5th Anniversary Contest

 

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#include <cstdio>
#include <cstring>
#include <cmath>
#include <algorithm>
using namespace std;
typedef long long LL;
const int maxn=1e6+1;
LL s[maxn],q[maxn],b;
int main()
{
    LL n, a;
    while(~scanf("%lld%lld%lld",&n,&a,&b)){
        LL front=0,rear=0;
        LL ans=1,x=1;
        for(LL i=1;i<=n;i++){
            LL l=max(1LL,i-a);
            x=x*a%b;
            while(front<rear&&x<s[rear-1])
                rear--;
            s[rear]=x;
            q[rear++]=i;
            while(front<rear&&l>q[front])
                front++;
            ans=ans*s[front]%b;
        }
        printf("%lld\n",ans);
    }
    return 0;
}