carloscn
commented
1 year ago Analysis
pub fn subset_xor_sum(nums: Vec<i32>) -> i32
{
let len:usize = nums.len();
if len < 1 {
return 0;
}
let mut ret:i32 = 0;
let (mut num, mut n, mut j, mut k) =
(1 << len, 0, 0, 0);
for i in 0..num {
j = i;
k = 0 as usize;
n = 0 as usize;
let mut t_buf:Vec<i32> = vec![0; i];
while j != 0 {
if j & 1 == 1 {
t_buf[n] = nums[k];
n += 1;
}
j >>= 1;
k += 1;
}
let mut xor_sum:i32 = 0;
for e in t_buf {
xor_sum ^= e;
}
ret += xor_sum;
}
return ret;
}
Description
The XOR total of an array is defined as the bitwise XOR of all its elements, or 0 if the array is empty.
For example, the XOR total of the array [2,5,6] is 2 XOR 5 XOR 6 = 1. Given an array nums, return the sum of all XOR totals for every subset of nums.
Note: Subsets with the same elements should be counted multiple times.
An array a is a subset of an array b if a can be obtained from b by deleting some (possibly zero) elements of b.
Example 1:
Input: nums = [1,3] Output: 6 Explanation: The 4 subsets of [1,3] are:
Example 2:
Input: nums = [5,1,6] Output: 28 Explanation: The 8 subsets of [5,1,6] are:
Example 3:
Input: nums = [3,4,5,6,7,8] Output: 480 Explanation: The sum of all XOR totals for every subset is 480.
Constraints:
1 <= nums.length <= 12 1 <= nums[i] <= 20