hdu5666 Segment (俄罗斯乘法)

#include<cstdio>
#include<cstring>
#include<iostream>
#include<sstream>
#include<algorithm>
#include<vector>
#include<bitset>
#include<set>
#include<queue>
#include<stack>
#include<map>
#include<cstdlib>
#include<cmath>
#define PI 2*asin(1.0)
#define LL long long
#define pb push_back
#define pa pair<int,int>
#define clr(a,b) memset(a,b,sizeof(a))
#define lson lr<<1,l,mid
#define rson lr<<1|1,mid+1,r
#define bug(x) printf("%d++++++++++++++++++++%d\n",x,x)
#define key_value ch[ch[root][1]][0]C:\Program Files\Git\bin
const int  MOD = 1000000007;
const int N = 500+15;
const int maxn = 60000+1000;
const int letter = 130;
const int INF = 1e17;
const double pi=acos(-1.0);
const double eps=1e-8;
using namespace std;
inline int read()
{
int x=0,f=1;char ch=getchar();
while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
return x*f;
}
LL p,q,x,y;
LL cc(LL a,LL b){
LL ans=0,pc=a;
while(b){
if(b&1){
ans=(ans+pc)%p;
b--;
}
else {
pc=(pc*2)%p;
b=b/2;
}
}
return ans;
}
int main(){
int T;
scanf("%d",&T);
while(T--){
scanf("%I64d%I64d",&q,&p);
if(q<=2) {puts("0");continue;}
LL x,y;
if((q-2)&1) x=q-2,y=(q-1)/2ll;
else x=(q-2)/2ll,y=q-1;
LL ans=cc(x,y);
printf("%I64d\n",ans);
}
return 0;
}