Binary Search Algorithm

Author: OmkarPathak

CompetitiveProgramming/HackerEarth/Algorithms/Searching/P07_DiscoverTheMonk.py

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+# You are given an array A of size N, and Q queries to deal with. For each query, you are given an integer X, and
+# you're supposed to find out if X is present in the array A or not.
+#
+# Input:
+# The first line contains two integers, N and Q, denoting the size of array A and number of queries. The second line
+# contains N space separated integers, denoting the array of elements Ai. The next Q lines contain a single integer X
+# per line.
+#
+# Output:
+# For each query, print YES if the X is in the array, otherwise print NO.
+#
+# Constraints:
+# 1 <= N, Q <= 105
+# 1 <= Ai <= 109
+# 1 <= X <= 109
+#
+# SAMPLE INPUT
+# 5 10
+# 50 40 30 20 10
+# 10
+# 20
+# 30
+# 40
+# 50
+# 60
+# 70
+# 80
+# 90
+# 100
+#
+# SAMPLE OUTPUT
+# YES
+# YES
+# YES
+# YES
+# YES
+# NO
+# NO
+# NO
+# NO
+# NO
+
+# Using binary search (non-efficient)
+n, q = map(int, input().split())
+array = [int(i) for i in input().split()]
+array.insert(0, 0)
+array.sort()
+
+def binarySearch(low, high, element):
+  while(low <= high):
+    mid = (low + high) // 2
+    try:
+      if array[mid] == element:
+        return mid
+      elif array[mid] < element:
+        low = mid + 1
+      else:
+        high = mid - 1
+    except IndexError:
+      return False
+
+for i in range(q):
+    number = int(input())
+    ans = binarySearch(0,len(array), number)
+    if ans:
+        print('YES')
+    else:
+        print('NO')
+
+# using traditional python (set as they are hashtables, hence efficient)
+in_ = input().split()
+arr = [x for x in input().split()]
+arr =set(arr)   # since python set is a hashtable and O(n) in hashtbale is O(1)
+for i in range(int(in_[1])):
+    if input() in arr:
+        print("YES")
+    else:
+        print("NO")