floor_or_ceil_using_binary_search.py

searches/floor_or_ceil_using_binary_search.py

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+def find_floor(arr, n, x):
+    low = 0
+    high = n - 1
+    ans = -1
+
+    while low <= high:
+        mid = (low + high) // 2
+        # maybe an answer
+        if arr[mid] <= x:
+            ans = arr[mid]
+            # look for smaller index on the left
+            low = mid + 1
+        else:
+            high = mid - 1  # look on the right
+
+    return ans
+
+
+def find_ceil(arr, n, x):
+    low = 0
+    high = n - 1
+    ans = -1
+
+    while low <= high:
+        mid = (low + high) // 2
+        # maybe an answer
+        if arr[mid] >= x:
+            ans = arr[mid]
+            # look for smaller index on the left
+            high = mid - 1
+        else:
+            low = mid + 1  # look on the right
+
+    return ans
+
+
+def get_floor_and_ceil(arr, n, x):
+    f = find_floor(arr, n, x)
+    c = find_ceil(arr, n, x)
+    return (f, c)
+
+
+# sample test cas
+# arr = [3, 4, 4, 7, 8, 10]
+# n = 6
+# x = 5
+# ans = get_floor_and_ceil(arr, n, x)
+# print("The floor and ceil are:", ans[0], ans[1])