Merge pull request #24 from alequisk/master

Adicionando solução em Python para o problema #3248 da categoria Estrutura de Dados

Estruturas e Bibliotecas/URI 3248.py

@@ -0,0 +1,33 @@
+def add(bit, i, val, sz):
+  while i <= sz:
+    bit[i] += val
+    i += i & -i
+
+def query(bit, i):
+  ret = 0
+  while i > 0:
+    ret += bit[i]
+    i -= i & -i
+  return ret
+
+N = int(input())
+arr = list(map(int, input().strip().split()))
+
+bitleft = [0] * (N + 1)
+bitright = [0] * (N + 1)
+
+for i in range(2, N):
+  add(bitright, arr[i], 1, N)
+
+add(bitleft, arr[0], 1, N)
+
+answer = 0
+for i in range(1, N - 1):
+  greaterLeft = query(bitleft, N) - query(bitleft, arr[i])
+  lessRight = query(bitright, arr[i] - 1)
+
+  answer += greaterLeft * lessRight
+  add(bitleft, arr[i], 1, N)
+  add(bitright, arr[i + 1], -1, N)
+
+print(answer)