daily: sum of all subset XOR totals

Rust version of bit manipulation.

Author: aucker

Diff for: rust/Cargo.toml

@@ -15,3 +15,7 @@ test = true
 [[bin]]
 name = "lca_deepest_leaves"
 path = "src/tree/25-Apr4.rs"
+
+[[bin]]
+name = "subset_xor_sum"
+path = "src/bit_manipulation/25-Apr5.rs"

Diff for: rust/src/bit_manipulation/25-Apr5.rs

@@ -0,0 +1,45 @@
+pub struct Solution {}
+
+impl Solution {
+    pub fn subset_xor_sum(nums: Vec<i32>) -> i32 {
+        let n = nums.len();
+        nums.into_iter().reduce(|or, x| or | x).unwrap() << (n - 1)
+    }
+}
+
+fn main() {
+    println!("subset xor sum implementation");
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    fn test_subset_xor_sum_example1() {
+        let nums = vec![1, 3];
+        assert_eq!(Solution::subset_xor_sum(nums), 6);
+        // Subsets: [1], [3], [1,3]
+        // XOR sums: 1 + 3 + 2 = 6
+    }
+
+    #[test]
+    fn test_subset_xor_sum_example2() {
+        let nums = vec![5, 1, 6];
+        assert_eq!(Solution::subset_xor_sum(nums), 28);
+        // Subsets: [5], [1], [6], [5,1], [5,6], [1,6], [5,1,6]
+        // XOR sums: 5 + 1 + 6 + 4 + 3 + 7 + 2 = 28
+    }
+
+    #[test]
+    fn test_subset_xor_sum_single_element() {
+        let nums = vec![2];
+        assert_eq!(Solution::subset_xor_sum(nums), 2);
+    }
+
+    // #[test]
+    // /// We don't test the empty case
+    // fn test_subset_xor_sum_empty() {
+    //     let nums = vec![];
+    //     assert_eq!(Solution::subset_xor_sum(nums), 0);
+    // }
+}