快速乘模數

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#include<iostream>#include<cstring>#include<cstdio>#include<algorithm>#define LL long long#define MOD 23333333333using namespace std;LL n,m;LL qmul(LL a, LL b, LL c){    LL ans = 0;    a = a%c;    while(b)    {        if(b&1)    ans = (ans+a)%c;        b >>= 1;        a = (a+a)%c;    }    return ans;}int main(){    while(~scanf("%lld%lld",&n,&m))    {        LL x = m/3,y = m%3,ans = 0;        if(x%2) ans = qmul(x*3,(2*n+x+1)/2,MOD);        else    ans = qmul(x*3/2,2*n+x+1,MOD);        for(int i = 0;i < y;i++)   ans = (ans+n+x+i)%MOD;        printf("%lld\n",ans);    }    return 0;}//XDOJ1182

 

快速乘模數