Python Array Data structure

Author: urperfectdude

array/all_num_div.py DataStructure/array/all_num_div.py

@@ -1,23 +1,23 @@
-# Find the equilibrium index of an array. An equilibrium index is such that
-# the sum of elements to the left of it is equal to sum of elements to the right
-# of it
-
-def find_equi(arr):
-    total_sum = sum(arr)
-
-    left_sum = 0 
-
-    for i, num in enumerate(arr):
-        
-        total_sum -= num
-        
-        if left_sum == total_sum:
-            return i
-
-        left_sum += num
-
-    return -1
-
-
-arr = [-7, 1, 5, 2, -4, 3, 0] 
-print(find_equi(arr))
+# Find the equilibrium index of an array. An equilibrium index is such that
+# the sum of elements to the left of it is equal to sum of elements to the right
+# of it
+
+def find_equi(arr):
+    total_sum = sum(arr)
+
+    left_sum = 0 
+
+    for i, num in enumerate(arr):
+        
+        total_sum -= num
+        
+        if left_sum == total_sum:
+            return i
+
+        left_sum += num
+
+    return -1
+
+
+arr = [-7, 1, 5, 2, -4, 3, 0] 
+print(find_equi(arr))

array/binary_search_infinite_array.py DataStructure/array/binary_search_infinite_array.py

@@ -1,16 +1,16 @@
-# Rearrange an array such that numbers at even indexes are greater than numbers 
-# at odd indexes
-
-def rearrange(arr):
-    for i in range(1, len(arr)):
-        if i % 2 == 0:
-            if arr[i] > arr[i-1]:
-                arr[i-1], arr[i] = arr[i], arr[i-1]
-        else:
-            if arr[i] < arr[i-1]:
-                arr[i-1], arr[i] = arr[i], arr[i-1]
-    print(arr)
-
-
-arr = [ 1, 3, 2, 2, 5 ]
+# Rearrange an array such that numbers at even indexes are greater than numbers 
+# at odd indexes
+
+def rearrange(arr):
+    for i in range(1, len(arr)):
+        if i % 2 == 0:
+            if arr[i] > arr[i-1]:
+                arr[i-1], arr[i] = arr[i], arr[i-1]
+        else:
+            if arr[i] < arr[i-1]:
+                arr[i-1], arr[i] = arr[i], arr[i-1]
+    print(arr)
+
+
+arr = [ 1, 3, 2, 2, 5 ]
 rearrange(arr)

array/duplicate.py DataStructure/array/duplicate.py

@@ -1,39 +1,39 @@
-# Minimum swaps required to bring all elements less than or equal to k together
-
-def min_swaps(arr, k):
-    # First find out how many elements are there which are less than or 
-    # equal to k
-    count = 0
-    for i in arr:
-        if i <= k:
-            count += 1
-
-    # This count defines a window - inside this window all our elements should 
-    # be placed
-    # Find the count of bad elements - elements which are more than k and that will be
-    # our starting answer as we will have to swap them out
-    bad = 0
-    for i in range(0, count):
-        if arr[i] > k:
-            bad += 1
-
-    ans = bad
-    j = count
-
-    for i in range(0, len(arr)):
-        if j == len(arr):
-            break
-
-        if arr[i] > k:
-            bad -= 1  # because we have moved the bad element out of the window
-        
-        if arr[j] > k:
-            bad += 1
-
-        ans = min(bad, ans)
-        j += 1
-
-    print('answer - ', ans)
-
-arr = [2,7,9,5,8,7,4]
+# Minimum swaps required to bring all elements less than or equal to k together
+
+def min_swaps(arr, k):
+    # First find out how many elements are there which are less than or 
+    # equal to k
+    count = 0
+    for i in arr:
+        if i <= k:
+            count += 1
+
+    # This count defines a window - inside this window all our elements should 
+    # be placed
+    # Find the count of bad elements - elements which are more than k and that will be
+    # our starting answer as we will have to swap them out
+    bad = 0
+    for i in range(0, count):
+        if arr[i] > k:
+            bad += 1
+
+    ans = bad
+    j = count
+
+    for i in range(0, len(arr)):
+        if j == len(arr):
+            break
+
+        if arr[i] > k:
+            bad -= 1  # because we have moved the bad element out of the window
+        
+        if arr[j] > k:
+            bad += 1
+
+        ans = min(bad, ans)
+        j += 1
+
+    print('answer - ', ans)
+
+arr = [2,7,9,5,8,7,4]
 min_swaps(arr, 5)

array/duplicates.py DataStructure/array/duplicates.py

@@ -1,22 +1,22 @@
-# A peak element is an element such that both of its neighbours are smaller than it
-# In case of corner elements, consider only one neighbour
-
-
-def peak(arr, low, high):
-    n = len(arr)
-
-    while low <= high:
-        mid = low + (high - low) / 2
-        mid = int(mid)
-        
-        if (mid == 0 or arr[mid-1] <= arr[mid]) and (mid == n-1 or arr[mid+1] <= arr[mid]):
-            return(arr[mid])
-
-        elif mid > 0 and arr[mid-1] > arr[mid]:
-            high = mid - 1
-
-        else:
-            low = mid + 1
-
-arr = [1, 3, 20, 4, 1, 0]
+# A peak element is an element such that both of its neighbours are smaller than it
+# In case of corner elements, consider only one neighbour
+
+
+def peak(arr, low, high):
+    n = len(arr)
+
+    while low <= high:
+        mid = low + (high - low) / 2
+        mid = int(mid)
+        
+        if (mid == 0 or arr[mid-1] <= arr[mid]) and (mid == n-1 or arr[mid+1] <= arr[mid]):
+            return(arr[mid])
+
+        elif mid > 0 and arr[mid-1] > arr[mid]:
+            high = mid - 1
+
+        else:
+            low = mid + 1
+
+arr = [1, 3, 20, 4, 1, 0]
 print(peak(arr, 0, len(arr) - 1))

array/dutch_flag_problem.py DataStructure/array/dutch_flag_problem.py

@@ -1,23 +1,23 @@
-# Rearragne positive and negative numbers in an array such that they appear
-# alternately. If there are more numbers of any one kind, put them at the end
-
-def rearrange(arr):
-    i = -1
-
-    for j in range(len(arr)):
-        if arr[j] < 0:
-            i += 1  # maintaining index of the last negative number
-            arr[j], arr[i] = arr[i], arr[j]
-
-    pos = i + 1  # index of first positive number
-    neg = 0  # index of first negative number
-
-    while pos < len(arr) and neg < pos and arr[neg] < 0:
-        arr[pos], arr[neg] = arr[neg], arr[pos]
-        pos += 1
-        neg += 2
-
-    print(arr)
-
-arr = [-1, 2, -3, 4, 5, 6, -7, 8, 9]
+# Rearragne positive and negative numbers in an array such that they appear
+# alternately. If there are more numbers of any one kind, put them at the end
+
+def rearrange(arr):
+    i = -1
+
+    for j in range(len(arr)):
+        if arr[j] < 0:
+            i += 1  # maintaining index of the last negative number
+            arr[j], arr[i] = arr[i], arr[j]
+
+    pos = i + 1  # index of first positive number
+    neg = 0  # index of first negative number
+
+    while pos < len(arr) and neg < pos and arr[neg] < 0:
+        arr[pos], arr[neg] = arr[neg], arr[pos]
+        pos += 1
+        neg += 2
+
+    print(arr)
+
+arr = [-1, 2, -3, 4, 5, 6, -7, 8, 9]
 rearrange(arr)