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Author: Saptarshi-prog

Week 4/Binary Search.py

@@ -0,0 +1,22 @@
+seq = [int(i) for i in input().split()]
+search_seq = [int(i) for i in input().split()]
+n = seq[0]
+seq = seq[1:]
+
+def binary_search(seq, elt, r):
+    l = 0
+    while l<=r: 
+        m = (l+r)//2
+        if elt > seq[m]:
+            l = m + 1
+        elif elt < seq[m]:
+            r = m - 1
+        else:
+            return m
+    return -1
+
+soln = list()
+for i in search_seq[1:]:
+    ans = binary_search(seq, i, n-1)
+    soln.append(ans)
+print(' '.join([str(i) for i in soln]))

Week 4/Inversion.py

@@ -0,0 +1,36 @@
+def merge(left, right):
+    i, j, inversion_counter = 0, 0, 0
+    final = list()
+    while i < len(left) and j< len(right):
+        if left[i] <= right[j]:
+            final.append(left[i])
+            i += 1
+        else:
+            final.append(right[j])
+            inversion_counter += len(left) - i
+            j += 1
+
+    final += left[i:]
+    final += right[j:]
+        
+    return final, inversion_counter
+
+def mergesort(arr):
+    global tot_count
+    if len(arr) <= 1:
+        return arr
+    mid = len(arr)//2
+
+    left = mergesort(arr[:mid])
+    right = mergesort(arr[mid:])
+
+    sorted_arr, temp = merge(left, right)
+    tot_count += temp
+
+    return sorted_arr
+
+tot_count = 0
+n = int(input())
+seq = [int(i) for i in input().split()]
+mergesort(seq)
+print(tot_count)

Week 4/Majority Elements.py

@@ -0,0 +1,27 @@
+n = int(input())
+seq = [int(i) for i in input().split()]
+
+
+def divide_func(seq, l, r):
+    if l+1==r:
+        return seq[l]
+    elif l+2==r:
+        return seq[l]
+    m = (l+r)//2
+    left = divide_func(seq, l, m)
+    right = divide_func(seq, m, r)
+
+    c1, c2 = 0, 0
+    for i in seq[l:r]:
+        if i == left:
+            c1+=1
+        elif i == right:
+            c2+=1
+    if c1>(r-l)//2 and left != -1:
+        return left
+    elif c2>(r-l)//2 and right != -1:
+        return right
+    else: 
+        return -1
+
+print(int(divide_func(seq, 0, n) != -1))