Improved task 744.

src/main/java/g0701_0800/s0744_find_smallest_letter_greater_than_target/Solution.java

@@ -1,29 +1,24 @@
 package g0701_0800.s0744_find_smallest_letter_greater_than_target;
 
 // #Easy #Array #Binary_Search #Binary_Search_I_Day_4
-// #2022_03_25_Time_0_ms_(100.00%)_Space_42.5_MB_(91.35%)
+// #2022_04_30_Time_0_ms_(100.00%)_Space_47.4_MB_(68.35%)
 
 public class Solution {
     public char nextGreatestLetter(char[] letters, char target) {
-        if (letters[0] > target) {
-            return letters[0];
+        int start = 0;
+        int end = letters.length - 1;
+        // If target is greater than last element return first element of the array.
+        if (letters[letters.length - 1] <= target) {
+            return letters[start];
         }
-        int left = 0;
-        int right = letters.length - 1;
-        while (left < right) {
-            int mid = left + (right - left) / 2;
-            if (letters[mid] > target) {
-                while (letters[mid] > target) {
-                    mid--;
-                }
-                return letters[++mid];
+        while (start < end) {
+            int mid = start + (end - start) / 2;
+            if (letters[mid] <= target) {
+                start = mid + 1;
             } else {
-                left = mid + 1;
+                end = mid;
             }
         }
-        if (right < letters.length && letters[right] > target) {
-            return letters[right];
-        }
-        return letters[0];
+        return letters[start];
     }
 }

src/test/java/g0701_0800/s0744_find_smallest_letter_greater_than_target/SolutionTest.java

@@ -23,4 +23,10 @@ void nextGreatestLetter3() {
         assertThat(
                 new Solution().nextGreatestLetter(new char[] {'c', 'f', 'j'}, 'd'), equalTo('f'));
     }
+
+    @Test
+    void nextGreatestLetter4() {
+        assertThat(
+                new Solution().nextGreatestLetter(new char[] {'c', 'f', 'j'}, 'k'), equalTo('c'));
+    }
 }