704. Binary Search: AC

Author: tan-wei

src/solution/mod.rs

@@ -512,3 +512,4 @@ mod s0699_falling_squares;
 mod s0700_search_in_a_binary_search_tree;
 mod s0701_insert_into_a_binary_search_tree;
 mod s0703_kth_largest_element_in_a_stream;
+mod s0704_binary_search;

src/solution/s0704_binary_search.rs

@@ -0,0 +1,73 @@
+/**
+ * [0704] Binary Search
+ *
+ * Given an array of integers nums which is sorted in ascending order, and an integer target, write a function to search target in nums. If target exists, then return its index. Otherwise, return -1.
+ * You must write an algorithm with O(log n) runtime complexity.
+ *  
+ * Example 1:
+ *
+ * Input: nums = [-1,0,3,5,9,12], target = 9
+ * Output: 4
+ * Explanation: 9 exists in nums and its index is 4
+ *
+ * Example 2:
+ *
+ * Input: nums = [-1,0,3,5,9,12], target = 2
+ * Output: -1
+ * Explanation: 2 does not exist in nums so return -1
+ *
+ *  
+ * Constraints:
+ *
+ * 	1 <= nums.length <= 10^4
+ * 	-10^4 < nums[i], target < 10^4
+ * 	All the integers in nums are unique.
+ * 	nums is sorted in ascending order.
+ *
+ */
+pub struct Solution {}
+
+// problem: https://leetcode.com/problems/binary-search/
+// discuss: https://leetcode.com/problems/binary-search/discuss/?currentPage=1&orderBy=most_votes&query=
+
+// submission codes start here
+
+impl Solution {
+    pub fn search(nums: Vec<i32>, target: i32) -> i32 {
+        let (mut low, mut high) = (0, nums.len());
+        while low < high {
+            let mid = low + (high - low) / 2;
+            match nums[mid].cmp(&target) {
+                std::cmp::Ordering::Equal => return mid as i32,
+                std::cmp::Ordering::Less => low = mid + 1,
+                std::cmp::Ordering::Greater => high = mid,
+            }
+        }
+        -1
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_0704_example_1() {
+        let nums = vec![-1, 0, 3, 5, 9, 12];
+        let target = 9;
+        let result = 4;
+
+        assert_eq!(Solution::search(nums, target), result);
+    }
+
+    #[test]
+    fn test_0704_example_2() {
+        let nums = vec![-1, 0, 3, 5, 9, 12];
+        let target = 2;
+        let result = -1;
+
+        assert_eq!(Solution::search(nums, target), result);
+    }
+}