搜狐公司的测评

搜狐公司的测评题目(C/C++) [Dev-C++]

#include  <stdio.h> 
#include  <stdlib.h> 
//#include  <stdint.h> 
#include  <assert.h> 
#include  <string.h> 

typedef unsigned int uint32_t;
typedef unsigned char uint8_t;

/*******************************************************************************
 * 搜狐评测题，通过加密和解密两个步骤 
 ******************************************************************************/

int  encode(constvoid*  raw_in,  void*  raw_out,  uint32_t  password,  size_t  len) 
{ 
const  uint8_t*in=  (const  uint8_t*)raw_in; 
    uint8_t*out=  (uint8_t*)raw_out; 
// 对于 a = b ^ c 来说； 可以 b = a ^ c = b ^ c ^ c; 即对于下面中
// 的所有 ^ 都只要重新来一次 ^ 就OK了 
    uint32_t  seed  =  password  ^0xa4b9cdddu; 
for  (size_t  i  =0  ;  i  <  len;  ++i)  { 
// 输入首先右移一位; 存放在a中，即输入的高7位存放在a的低7位
// a = zxxx xxxx  
        uint8_t  a  =  (  in[i]  ^  seed  )  >>1; 
// 下面这句是将输入左移 19，然后右移12位，相当于左移了7位
//  即输入的低1位存在b的最高位  b = xzzz zzzz 
        uint8_t  b  =  (  (  ((uint32_t)in[i])  <<19  )  ^  seed  )  >>  (19-7); 
// 127 = 0111 1111 即将a的第7位置为0； a = 0\xxx xxxx(原来in的高7位)  
        a  &=127; 
// 128 = 1000 0000 即将b的第6~0位置为0  b = x(原来in的低1位)/000 0000
        b  &=128; 
// 下面这句没有用，因为b右移三位，直接变成了0； 再与a异或的话就直接是a原来的值了 
        a  =127&  (  a  ^  (b  <<3)); 
// 最后out[i] 存放的就是将in[i]对调了 ;
out[i]  =  a  |  b; 
// 种子的话，加密和解密的是一样的，只是这里的out[i]改为in[i]就OK了，因为加密
// 算法中的输出就是解密算法时的输入; 而初始种子都是一样的 
        seed  =  (((seed  <<7)  ^  seed  ^out[i])  +144123481); 
    } 
} 


int  decode(constvoid*  raw_in,  void*  raw_out,  uint32_t  password,  size_t  len) 
{ 
const  uint8_t*in=  (const  uint8_t*)raw_in; 
    uint8_t*out=  (uint8_t*)raw_out; 
//
    uint32_t  seed  =  password  ^0xa4b9cdddu; 
for  (size_t  i  =0  ;  i  <  len;  ++i)  { 
// 将经过加密的输入in[i]的低7位放在a高7位 
        uint8_t a = ( in[i] <<1 ) ^ seed;
// 将经过加密的输入in[i]的高1位放在b的低1位 
        uint8_t b = (((uint32_t)in[i] << (19-7))^seed) >>19;
// 254 = 1111 1110 将a的最后1位强制清零;注意加密中存放在a中是低7位，所以与127与；而这里是存在a的高七位，所以是254 
        a &=254;
// 将b高7位强制清零 
        b &=1;
// 两者异或就得到了加密前的数据了 
out[i] = a|b;
// 种子解释看加密 
        seed  =  (((seed  <<7)  ^  seed  ^in[i])  +144123481); 
    } 
} 
int  main() 
{ 
const  uint8_t  buf1[]  =  {0xbe,  0x58,  0xd5,  0xcb,  0xc7,  0x85,  0x84,  0x3a,  0xa2,  0x30,  0xa3,  0x36,  0x5f,  0x43,  0xc9,  0x53,  0x67,  0xf3,  0xac,  0xed,  0xc4,  0x38,  0xb7,  0xdf,  0xec,  0x51,  0x09,  0xbf,  0x2a,  0x32,  0x6b,  0x42,  0x32,  0x71,  0xe0,  0x93,  0x8b,  0xeb,  0x1c,  0xd2,  0x62,  0x6a,  0xb6,  0x10,  0x09,  0x89,  0xb6,  0xb1,  0x29,  0x31,  0xd2,  0xb9,  0xa0,  0xb5,  0x5d,  0x40,  0xf8,  0x74,  0xc3,  0x35,  0x70,  0x95,  0x2a,  0x0b,  0x5a,  0x82,  0x51,  0x05,  }; 
    uint8_t  buf2[100]  =  {}; 
const  uint32_t  password  =0x1c1c2c6bu; 
const  size_t  len  =sizeof(buf1); 
    decode(buf1,  buf2,  password,  len); 
    printf("%s\n",  buf2); 
     system("PAUSE");
return EXIT_SUCCESS;
} 

　　输出结果:

#include  <stdio.h> 
#include  <stdlib.h> 
//#include  <stdint.h> 
#include  <assert.h> 
#include  <string.h> 
typedef unsigned int uint32_t;
typedef unsigned char uint8_t;

int  encode(constvoid*  raw_in,  void*  raw_out,  uint32_t  password,  size_t  len) 
{ 
const  uint8_t*in=  (const  uint8_t*)raw_in; 
    uint8_t*out=  (uint8_t*)raw_out; 

    uint32_t  seed  =  password  ^0x91e69948u; 
for  (size_t  i  =0  ;  i  <  len;  ++i)  { 
    
        uint8_t  a  =  (  in[i]  ^  seed  )  >>5; 
        
        uint8_t  b  =  (  (  ((uint32_t)in[i])  <<19  )  ^  seed  )  >>  (19-3); 
        a  &=7; 
        b  &=248; 
        a  =7&  (  a  ^  (b  <<3)); 
out[i]  =  a  |  b; 
        seed  =  ((seed  ^in[i])  *536513+in[i]); 
    } 
return0;
} 


int  decode(constvoid*  raw_in,  void*  raw_out,  uint32_t  password,  size_t  len) 
{ 
const  uint8_t*in=  (const  uint8_t*)raw_in; 
    uint8_t*out=  (uint8_t*)raw_out; 

    uint32_t  seed  =  password  ^0x91e69948u; 
for  (size_t  i  =0  ;  i  <  len;  ++i)  { 
        uint8_t a = (in[i] <<5) ^ seed;
        uint8_t b = ( ((uint32_t)in[i] << (19-3)) ^seed ) >>19;
        a &=224;
        b &=31;
out[i] = a | b;
        seed  =  ((seed  ^out[i])  *536513+out[i]); 
    } 
return0;
} 
int  main() 
{ 
const  uint8_t  buf1[]  =  {0xfe,  0x7c,  0x75,  0xf8,  0x85,  0x14,  0x1b,  0x21,  0xee,  0x13,  0x52,  0xb6,  0xc8,  0xfd,  0x06,  0x40,  0x92,  0x7c,  }; 
    uint8_t  buf2[100]  =  {}; 
const  uint32_t  password  =0x27430952u; 
const  size_t  len  =sizeof(buf1); 
    decode(buf1,  buf2,  password,  len); 
    printf("%s\n",  buf2); 
    system("PAUSE");
return0;
} 

　　输出结果