Merge pull request #9 from rust-interview/dev

add single-number

Author: 0xmountaintop

README.md

@@ -51,9 +51,10 @@ cargo test
 0136 | [Single Number](https://leetcode.com/problems/single-number/) | [C++](https://github.com/kamyu104/LeetCode-Solutions/blob/master/C++/single-number.cpp), [Python](https://github.com/kamyu104/LeetCode-Solutions/blob/master/Python/single-number.py) <br> [Rust](./kamyu104/src/single_number.rs) | _O(n)_       | _O(1)_          | Easy         |||
 0137 | [Single Number II](https://leetcode.com/problems/single-number-ii/) | [C++](https://github.com/kamyu104/LeetCode-Solutions/blob/master/C++/single-number-ii.cpp), [Python](https://github.com/kamyu104/LeetCode-Solutions/blob/master/Python/single-number-ii.py) <br> [Rust](./kamyu104/src/single_number_ii.rs) | _O(n)_ | _O(1)_          | Medium         |||
 0190 | [Reverse Bits](https://leetcode.com/problems/reverse-bits/)  | [C++](https://github.com/kamyu104/LeetCode-Solutions/blob/master/C++/reverse-bits.cpp), [Python](https://github.com/kamyu104/LeetCode-Solutions/blob/master/Python/reverse-bits.py) <br> [Rust](./kamyu104/src/reverse_bits.rs) | _O(1)_        | _O(1)_          | Easy           |||
+0191  |[Number of 1 Bits](https://leetcode.com/problems/number-of-1-bits/) | [C++](https://github.com/kamyu104/LeetCode-Solutions/blob/master/C++/number-of-1-bits.cpp), [Python](https://github.com/kamyu104/LeetCode-Solutions/blob/master/Python/number-of-1-bits.py) <br> [Rust](./kamyu104/src/number_of_1_bits.rs) | _O(1)_ | _O(1)_          | Easy           |||
 
 <!-- 
-0191  |[Number of 1 Bits](https://leetcode.com/problems/number-of-1-bits/) | [C++](./C++/number-of-1-bits.cpp) [Python](./Python/number-of-1-bits.py) | _O(1)_ | _O(1)_          | Easy           |||
+
 0201 | [Bitwise AND of Numbers Range](https://leetcode.com/problems/bitwise-and-of-numbers-range/) | [C++](./C++/bitwise-and-of-numbers-range.cpp) [Python](./Python/bitwise-and-of-numbers-range.py) | _O(1)_ | _O(1)_ | Medium ||
 0231 | [Power of Two](https://leetcode.com/problems/power-of-two/) | [C++](./C++/power-of-two.cpp) [Python](./Python/power-of-two.py) | _O(1)_ | _O(1)_ | Easy | LintCode |
 0260 | [Single Number III](https://leetcode.com/problems/single-number-iii/) | [C++](./C++/single-number-iii.cpp) [Python](./Python/single-number-iii.py) | _O(n)_ | _O(1)_          | Medium         ||

kamyu104/src/main.rs

@@ -1,3 +1,4 @@
+mod number_of_1_bits;
 mod reverse_bits;
 mod single_number;
 mod single_number_ii;

kamyu104/src/number_of_1_bits.rs

@@ -0,0 +1,42 @@
+// Time:  O(logn) = O(32)
+// Space: O(1)
+
+pub struct Solution {}
+
+impl Solution {
+    pub fn hamming_weight(mut n: u32) -> u8 {
+        let mut cnt: u8 = 0;
+        while n > 0 {
+            cnt += 1;
+            n &= n - 1;
+        }
+        return cnt;
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_hamming_weight() {
+        assert_eq!(
+            Solution::hamming_weight(
+                u32::from_str_radix("00000000000000000000000000001011", 2).unwrap()
+            ),
+            3
+        );
+        assert_eq!(
+            Solution::hamming_weight(
+                u32::from_str_radix("00000000000000000000000010000000", 2).unwrap()
+            ),
+            1
+        );
+        assert_eq!(
+            Solution::hamming_weight(
+                u32::from_str_radix("11111111111111111111111111111101", 2).unwrap()
+            ),
+            31
+        );
+    }
+}

kamyu104/src/single_number_ii.rs

@@ -54,7 +54,7 @@ mod tests {
     use super::*;
 
     #[test]
-    fn test_add() {
+    fn test_single_number() {
         assert_eq!(Solution1::single_number(vec![2, 2, 3, 2]), 3);
         assert_eq!(Solution1::single_number(vec![0, 1, 0, 1, 0, 1, 99]), 99);
         assert_eq!(Solution1::single_number(vec![0, 0, 0, 1, 1, 1, 5]), 5);