There are N coins kept on the table, numbered from 0 to N – 1. Initially, each coin is kept tails up. You have to perform two types of operations:
- Flip all coins numbered between A and B inclusive. This is represented by the command “0 A B”
- Answer how many coins numbered between A and B inclusive
are headsup. This is represented by the command “1 A B”.
The first line contains two integers, N and Q. Each of the next Q lines
Output 1 line for each of the queries of the form “1 A B” containing the required answer for the corresponding query.
Sample Input :
1 0 3
0 1 2
1 0 1
1 0 0
0 0 3
1 0 3
1 3 3
Sample Output :
1 <= N <= 100000
1 <= Q <= 100000
0 <= A <= B <= N - 1
It is a Simple problem related to fast input/ output processing. Key to this problem is using sys.stdin module instead of the default input() function.
- Initialize a Numpy array with N number of zeroes.
- For the value of p == 0. use negation to reverse the values in the array.
- For p == 1,
Calulatethe sum and print it.
import numpy as np import sys # Using sys.stdin.readline() since it is fast N,M = map(int,sys.stdin.readline().split()) # Initializing the Numpy Array L = np.zeros(N, dtype=bool) for _ in range(M): p,x,y = map(int, sys.stdin.readline().split()) if p == 0: L[x:y+1] = ~L[x:y+1] else: print(L[x:y+1].sum())
This code uses bitwise operators for speedy calculations. Bitwise operators can make you competitive life easy. Take our Quick Guide on bitwise operators to know more.