modified the binary searches, now implemented with pattern matching

2023_09_25/First_and_Last_Position_of_Element_in_Sorted_Array/src/main.rs

@@ -1,3 +1,5 @@
+use std::cmp::Ordering;
+
 struct Solution {}
 
 impl Solution {
@@ -11,11 +13,10 @@ impl Solution {
 
         while l <= r {
             let m = l + (r - l) / 2; // m = middle for the binary search
-            if target > nums[m as usize] {
-                l = m + 1;
-            } else if target < nums[m as usize] {
-                r = m - 1;
-            } else {
+            match target.cmp(&nums[m as usize]) {
+                Ordering::Less => r = m - 1,
+                Ordering::Greater => l = m + 1,
+                Ordering::Equal => {
                     i = m;
                     if left_bias {
                         r = m - 1;
@@ -24,6 +25,7 @@ impl Solution {
                     }
                 }
             }
+        }
         return i;
     }
 

2023_09_25/find-minimum-in-rotated-sorted-array/src/main.rs

@@ -1,3 +1,5 @@
+use std::cmp::Ordering;
+
 fn findMin(nums: Vec<i32>) -> i32 {
     let mut res = nums[0] as i32;
     // The left and right pointers of the binary search
@@ -5,26 +7,22 @@ fn findMin(nums: Vec<i32>) -> i32 {
 
     // Binary search
     while l <= r {
-        // If the left value is smaller than the right value,
-        // then the left value is the smallest
-        if nums[l] <= nums[r] {
+        match nums[l].cmp(&nums[r]) {
+            Ordering::Less | Ordering::Equal => { // The array is sorted
                 res = res.min(nums[l]);
                 break;
             }
-        // The middle value
-        let mid = l + (r - l) / 2;
-        // Update the smallest value
-        res = res.min(nums[mid]);
-
-        // If the left value is smaller than the middle value,
-        // then the smallest value is on the right side
-        if nums[l] <= nums[mid] {
+            Ordering::Greater => { // The array is rotated
+                let mid = l + (r - l) / 2; // The middle index
+                res = res.min(nums[mid]); // Update the minimum
+                if nums[l] <= nums[mid] { // The left half is sorted
                     l = mid + 1;
-        } else {
-            // Otherwise, the smallest value is on the left side
+                } else { // The right half is sorted
                     r = mid - 1;
                 }
             }
+        }
+    }
     return res as i32;
 }