Data commit

Task/Binary-search/Java/binary-search-1.java

@@ -0,0 +1,29 @@
+public class BinarySearchIterative {
+
+    public static int binarySearch(int[] nums, int check) {
+        int hi = nums.length - 1;
+        int lo = 0;
+        while (hi >= lo) {
+            int guess = (lo + hi) >>> 1;  // from OpenJDK
+            if (nums[guess] > check) {
+                hi = guess - 1;
+            } else if (nums[guess] < check) {
+                lo = guess + 1;
+            } else {
+                return guess;
+            }
+        }
+        return -1;
+    }
+
+    public static void main(String[] args) {
+        int[] haystack = {1, 5, 6, 7, 8, 11};
+        int needle = 5;
+        int index = binarySearch(haystack, needle);
+        if (index == -1) {
+            System.out.println(needle + " is not in the array");
+        } else {
+            System.out.println(needle + " is at index " + index);
+        }
+    }
+}

Task/Binary-search/Java/binary-search-2.java

@@ -0,0 +1,28 @@
+public class BinarySearchRecursive {
+
+    public static int binarySearch(int[] haystack, int needle, int lo, int hi) {
+        if (hi < lo) {
+            return -1;
+        }
+        int guess = (hi + lo) / 2;
+        if (haystack[guess] > needle) {
+            return binarySearch(haystack, needle, lo, guess - 1);
+        } else if (haystack[guess] < needle) {
+            return binarySearch(haystack, needle, guess + 1, hi);
+        }
+        return guess;
+    }
+
+    public static void main(String[] args) {
+        int[] haystack = {1, 5, 6, 7, 8, 11};
+        int needle = 5;
+
+        int index = binarySearch(haystack, needle, 0, haystack.length);
+
+        if (index == -1) {
+            System.out.println(needle + " is not in the array");
+        } else {
+            System.out.println(needle + " is at index " + index);
+        }
+    }
+}

Task/Binary-search/Java/binary-search-3.java

@@ -0,0 +1,8 @@
+import java.util.Arrays;
+
+int index = Arrays.binarySearch(array, thing);
+int index = Arrays.binarySearch(array, startIndex, endIndex, thing);
+
+// for objects, also optionally accepts an additional comparator argument:
+int index = Arrays.binarySearch(array, thing, comparator);
+int index = Arrays.binarySearch(array, startIndex, endIndex, thing, comparator);

Task/Binary-search/Java/binary-search-4.java

@@ -0,0 +1,4 @@
+import java.util.Collections;
+
+int index = Collections.binarySearch(list, thing);
+int index = Collections.binarySearch(list, thing, comparator);