Merge pull request #45 from prathamsharma92/prathamsharma92-patch-1-jump_search

Create jump_search.rb

Searches/jump_search.rb

@@ -0,0 +1,48 @@
+# Works only on sorted arrays.
+# Finding element by creating step in array and jump ahead by fixed steps and finding element using linear search inside that steped array.
+# Time Complexity: O(√n)
+
+def jump_search(arr, x)
+  n = arr.length;
+
+  # Finding block size to be jumped 
+  step = Math.sqrt(n);
+  prev = 0;
+
+  # Finding the block where element is 
+  # present (if it is present) 
+  while (arr[[step, n].min - 1] < x) do
+    prev = step;
+    step += Math.sqrt(n);
+    if (prev >= n)
+      return -1;
+    end
+  end
+
+  # Doing a linear search for x in block 
+  # beginning with prev. 
+  while (arr[prev] < x) do
+    prev = prev + 1;
+    # If we reached next block or end of 
+    # array, element is not present. 
+    if (prev == [step, n].min)
+      return -1;
+    end
+  end
+
+  # If element is found
+  if (arr[prev] == x)
+    return prev;
+  end
+
+  return -1;
+end
+
+puts "Enter a sorted space-separated list:"
+arr = gets.chomp.split(' ').map(&:to_i)
+puts "Enter the value to be searched:"
+value = gets.chomp.to_i
+
+index = jump_search(arr, value)
+
+puts index == -1 ? "Element not found" : "Number #{value} is at #{index}"