Input and Output

Input and Output in Python

In competitive programming, handling input and output efficiently is crucial. Python provides built-in functions to read from standard input and write to standard output.

Reading Input

You can read input using the input() function, which reads a line of input as a string. For example:

name = input("Enter your name: ")
print(f"Hello, {name}!")

For multiple inputs, you can use the split() method to separate the input into parts. For example:

# Array of Strings input
data = input("Enter data separated by space: ").split()
print(data) # Output: ['data1', 'data2', 'data3']

# Array of integers input
numbers = input("Enter numbers separated by space: ").split()
print(numbers) # Output: ['1', '2', '3']
numbers = [int(num) for num in numbers]  # Convert strings to integers
print(numbers) # Output: [1, 2, 3]

# Split with a custom delimiter
data = input("Enter data separated by comma: ").split(',') # Input: data1,data2,data3
print(data) # Output: ['data1', 'data2', 'data3']

Writing Output

You can write output using the print() function. For example:

result = 42
print(f"The result is: {result}")

Fast Input and Output

In competitive programming, you may need to handle large inputs and outputs efficiently. You can use sys.stdin and sys.stdout for faster input and output. Here's how:

import sys
# Fast input
input = sys.stdin.readline
# Fast output
print = sys.stdout.write

# Example of fast input and output
n = int(input())
for _ in range(n):
    data = input().strip()
    print(f"Processed: {data}\n")

Using sys.stdin.readline is faster than input(), and using sys.stdout.write can be more efficient than print() for large outputs. Remember to include a newline character (\n) when using sys.stdout.write to ensure proper formatting.

Summary

• Use input() for simple input and print() for simple output.
• For multiple inputs, use split() to separate them and convert to the desired type.
• For large inputs and outputs, consider using sys.stdin.readline and sys.stdout.write for better performance.