快速幂（二进方法）

#include <iostream>
using namespace std;

// Right to left binary

int quickPower( int base, int exp ){
    
    int res     = 1;
    int product = base;
    
    while( exp ){
        
        if( exp & 1 ){
            res *= product;
        }
        
        product *= product;
        exp     >>= 1;
        
    }
    
    return res;
    
}


int main(){
    
    cout << quickPower( 3, 4 );
    
    return 0;
    
}


// Left to right binary
int quickPower( int base, int exp ){
    
    int temp = exp;
    int comp = 1;
    int res  = 1;
    
    while( temp ){
        
        temp >>= 1;
        comp <<= 1;
        
    }
    
    comp >>= 1;
    
    while( comp ){
        
        res *= res;
        
        if( exp & comp )
            res *= base;

        comp >>= 1;
        
    }
    
    return res;
    
}


int main(){
    
    cout << quickPower( 3, 5 );
    
    return 0;
    
}