Fast Power-Take mode

Use two points to change the complexity from O (n) to O (Logn)

#include <iostream> #include <cstdio>using namespace std;///(b^n) mod m;  (a*b mod m) = (a mod m) * (b mod m) mod m       O (log n)//(b^n) mod m;  (a) MoD m = ((a mod m)-(b mod m) + N) mod m  )      O (log n)//(b^n) mod m;  (A + b) mod m = ((a mod m) + (b mod m) mod m  )       O (log n) int mod (int b,int n,int m)//bitwise operation {    int ans=1;    while (n) {        if (n&1)            ans= (ans*b)%m;        b= (b*b)%m;        n=n>>1;    }    return ans;} int mod_1 (int b,int n,int m)//  O (log n) recursive {    if (n==0) return 1;    int x=mod_1 (b,n/2,m);    Long Long ans= (long Long) x*x%m;    if (n%2) ans=ans*b%m;   N&1    return (int) ans; int main () {    int b,n,m;    while (scanf ("%d%d%d", &b,&n,&m))    {        printf ("%d  ", mod (b,n,m));        printf ("%d\n", Mod_1 (B,n,m));    }    return 0;} /**12996 227 37909  = = 7775*/

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Fast Power-Take mode