Code War每天一练第二天

Posted 2021-02-08 zch-boke

Given an array of one‘s and zero‘s convert the equivalent binary value to an integer.

Eg: [0, 0, 0, 1] is treated as 0001 which is the binary representation of 1.

 

Examples:

Testing: [0, 0, 0, 1] ==> 1
Testing: [0, 0, 1, 0] ==> 2
Testing: [0, 1, 0, 1] ==> 5
Testing: [1, 0, 0, 1] ==> 9
Testing: [0, 0, 1, 0] ==> 2
Testing: [0, 1, 1, 0] ==> 6
Testing: [1, 1, 1, 1] ==> 15
Testing: [1, 0, 1, 1] ==> 11

将字符数组转化成整数

res = x

ⁿ

+x

^n-1

+x

^n-2

.......x

¹

+x0

#include <stddef.h>

unsigned binary_array_to_numbers(const unsigned *bits, size_t count) {
  unsigned res = 0;
  for (size_t i = 0; i < count; i++)
    res = res << 1 | bits[i];
  return res;
}