add 704. Binary Search

src/solutions.rs

@@ -11,5 +11,6 @@ mod s_46_permutations;
 mod s_543_diameter_of_binary_tree;
 mod s_567_permutation_in_string;
 mod s_572_subtree_of_another_tree;
+mod s_704_binary_search;
 mod s_78_subset;
 mod s_79_word_search;

src/solutions/s_704_binary_search.rs

@@ -0,0 +1,47 @@
+struct Solution {}
+
+impl Solution {
+    pub fn search(nums: Vec<i32>, target: i32) -> i32 {
+        let mut left_ptr = 0;
+        let mut right_ptr = nums.len() as i32 - 1;
+        while left_ptr <= right_ptr {
+            let mid_ptr = (right_ptr + left_ptr) / 2;
+            match target.cmp(&nums[mid_ptr as usize]) {
+                std::cmp::Ordering::Less => {
+                    right_ptr = mid_ptr - 1;
+                }
+                std::cmp::Ordering::Equal => return mid_ptr as i32,
+                std::cmp::Ordering::Greater => {
+                    left_ptr = mid_ptr + 1;
+                }
+            }
+        }
+        return -1;
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_exist() {
+        let input = vec![-1, 0, 3, 5, 9, 12];
+        let res = Solution::search(input, 9);
+        assert_eq!(res, 4);
+    }
+
+    #[test]
+    fn test_not_exist() {
+        let input = vec![-1, 0, 3, 5, 9, 12];
+        let res = Solution::search(input, 2);
+        assert_eq!(res, -1);
+    }
+
+    #[test]
+    fn test_single_element() {
+        let input = vec![1];
+        let res = Solution::search(input, -1);
+        assert_eq!(res, -1);
+    }
+}