Write a program that counts the number of words on all input lines. (For this exercise and other exercises on this page, consider a word to be any sequence of printable characters.)
Write a program that prints the longest word found on any input line.
In the lecture, we considered these two programs:
(1)
n = int(input('Enter n: ')) a = [] for i in range(n): a.append(i)
(2)
n = int(input('Enter n: ')) a = [] for i in range(n): a = a + [i]
We found that program 1 runs in O(N), and program 2 runs in O(N2), an important difference.
Now consider this third program:
(3)
n = int(input('Enter n: ')) a = [] for i in range(n): a += [i]
Do you think it will run in O(N), or O(N2)? Perform an experiment to find out which is the case.
(Recall that on lists += is a synonym for Python's extend() method.)
Write a program that prints a histogram of the lengths of all words found in all input lines. For example, if the input is
there is a big green tree in the park on a sunny day
the program's output might look like this:
1: ** 2: *** 3: *** 4: ** 5: ***
Write a program that reads a square matrix of integers. The program should print the largest value in the matrix and the column number that contains it.
Input:
2 8 3 9 6 7 0 3 -1
Output:
Column 1 contains 9.
A matrix M is symmetric if Mij = Mji for all i and j. For example, here is a symmetric matrix:
1 2 3 2 5 4 3 4 6
Write a function that takes a square matrix M represented as a list of lists, and returns True if the matrix is symmetric.
The identity matrix of size N x N contains ones along its main diagonal, and zeroes everywhere else. For example, here is the identity matrix of size 4 x 4:
1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1
Write a function identity_matrix(n) that returns the identity matrix of size n x n, represented as a list of lists.
Write a program that reads a square matrix of integers. The program should print the largest sum of any row or column in the matrix.
Input:
2 4 8 10 5 3 7 1 9 6 9 4 2 2 8 3
Output:
32
Write a function that takes two matrices, and returns the sum of the matrices. Assume that the matrices have the same dimensions.
Write a function that takes two matrices, and returns the product of the matrices. Assume that the matrices have dimensions that are compatible for multiplication.
Solve Project Euler's problem 8:
Find the thirteen adjacent digits in the 1000-digit number that have the greatest product. What is the value of this product?
Read the input number as a series of lines from standard input.
Solve Project Euler's problem 9:
There exists exactly one Pythagorean triplet for which a + b + c = 1000. Find the product abc.