added alternative solution to GuessNumberHigherOrLower.java

Dipanjansur · Jun 4, 2018 · 3d5dc11 · 3d5dc11
1 parent fbbb6db
commit 3d5dc11
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Showing 2 changed files with 24 additions and 51 deletions.
diff --git a/company/google/GuessNumberHigherOrLower.java b/company/google/GuessNumberHigherOrLower.java
@@ -21,30 +21,19 @@
 
 public class GuessNumberHigherOrLower extends GuessGame {
     public int guessNumber(int n) {
-        return binarySearch(1, n);
-    }
-
-    private int binarySearch(int start, int end) {
-        if(start > end) {
-            return -1;
-        }
-
-        if(guess(start) == 0) {
-            return start;
+        int left = 1;
+        int right = n;
+        while(left <= right) {
+            int mid = left + (right - left) / 2;
+            if(guess(mid) == 0) {
+                return mid;
+            } else if(guess(mid) > 0) {
+                left = mid + 1;
+            } else {
+                right = mid;
+            }
         }
 
-        if(guess(end) == 0) {
-            return end;
-        }
-
-        int mid = start + (end - start) / 2;
-
-        if(guess(mid) == 0) {
-            return mid;
-        } else if(guess(mid) == 1) {
-            return binarySearch(mid + 1, end);
-        } else {
-            return binarySearch(start, mid - 1);
-        }
+        return -1;
     }
 }
diff --git a/leetcode/binary-search/GuessNumberHigherOrLower.java b/leetcode/binary-search/GuessNumberHigherOrLower.java
@@ -14,37 +14,21 @@
 
 // Return 6.
 
-/* The guess API is defined in the parent class GuessGame.
-   @param num, your guess
-   @return -1 if my number is lower, 1 if my number is higher, otherwise return 0
-      int guess(int num); */
-
 public class GuessNumberHigherOrLower extends GuessGame {
     public int guessNumber(int n) {
-        return binarySearch(1, n);
-    }
-
-    private int binarySearch(int start, int end) {
-        if(start > end) {
-            return -1;
-        }
-
-        if(guess(start) == 0) {
-            return start;
-        }
-
-        if(guess(end) == 0) {
-            return end;
+        int left = 1;
+        int right = n;
+        while(left <= right) {
+            int mid = left + (right - left) / 2;
+            if(guess(mid) == 0) {
+                return mid;
+            } else if(guess(mid) > 0) {
+                left = mid + 1;
+            } else {
+                right = mid;
+            }
         }
 
-        int mid = start + (end - start) / 2;
-
-        if(guess(mid) == 0) {
-            return mid;
-        } else if(guess(mid) == 1) {
-            return binarySearch(mid + 1, end);
-        } else {
-            return binarySearch(start, mid - 1);
-        }
+        return -1;
     }
 }