Homework 12026-06-22

Array Practice

Python lists · Use indexes · Write list functions · Print exact output

Requirements

5 required problems. Estimated time: 2 – 3 hours.
Only submit a Python version (.py) for each problem.
These are array/list problems. Read the input values into a Python list before calling the required function.
Use loops yourself. In Python, do not use sum, max, min, count, index, or sorted.
Output format must match the samples exactly.

Problems

1Array Sum

You are given n integers. Store them in a Python list, then write a function sum_array that returns the sum of all elements.

Input format

text

First line: one integer n.Second line: n integers.Constraint: 1 ≤ n ≤ 100

Output format

text

One line containing the sum of all elements.

Sample 1

Input

text

510 20 30 40 50

Output

text

Sample 2

Input

text

43 -1 8 0

Output

text

Sample 3

Input

text

Output

text

Required structure

array_sum.py

def sum_array(a):    # TODO: return the sum of all elements    passn = int(input())a = list(map(int, input().split()))print(sum_array(a))

Hint: Start with total = 0. Loop over every valid index and add a[i].

2Count Greater Than Target

You are given n integers and a target value. Store the integers in a Python list, then count how many elements are greater than the target.

Input format

text

First line: one integer n.Second line: n integers.Third line: one integer target.Constraint: 1 ≤ n ≤ 100

Output format

text

One line containing the count.

Sample 1

Input

text

580 91 76 88 9585

Output

text

Sample 2

Input

text

41 2 3 44

Output

text

Sample 3

Input

text

6-3 0 7 7 9 26

Output

text

Required structure

count_greater.py

def count_greater(a, target):    # TODO: count elements greater than target    passn = int(input())a = list(map(int, input().split()))target = int(input())print(count_greater(a, target))

Hint: This is a counting loop. Increase the counter only when a[i] > target.

3First Maximum Index

You are given n integers. Find the maximum value and the first index where it appears. Indexes start from 0.

Input format

text

First line: one integer n.Second line: n integers.Constraint: 1 ≤ n ≤ 100

Output format

text

Print one line:max=VALUE index=INDEX

Sample 1

Input

text

580 91 76 91 88

Output

text

max=91 index=1

Sample 2

Input

text

4-5 -2 -9 -2

Output

text

max=-2 index=1

Sample 3

Input

text

Output

text

max=42 index=0

Required structure

max_index.py

def index_of_first_max(a):    # TODO: return the first index of the maximum value    passn = int(input())a = list(map(int, input().split()))index = index_of_first_max(a)print(f"max={a[index]} index={index}")

Hint: Start with index 0 as the best index. Only update it when you find a strictly larger value.

4Replace Negatives with Zero

You are given n integers. Replace every negative number with 0, then print the modified list.

Input format

text

First line: one integer n.Second line: n integers.Constraint: 1 ≤ n ≤ 100

Output format

text

One line containing the modified values, separated by single spaces.

Sample 1

Input

text

6-3 0 7 -1 9 -5

Output

text

0 0 7 0 9 0

Sample 2

Input

text

41 2 3 4

Output

text

1 2 3 4

Sample 3

Input

text

3-1 -2 -3

Output

text

0 0 0

Required structure

replace_negative.py

def replace_negative(a):    # TODO: change every negative element to 0    passdef print_array(a):    # TODO: print all elements on one line    passn = int(input())a = list(map(int, input().split()))replace_negative(a)print_array(a)

Hint: This function changes the list in place. If a[i] < 0, assign a[i] = 0.

5Is Sorted

You are given n integers. Determine whether the list is sorted in non-decreasing order. Equal neighboring values are allowed.

Input format

text

First line: one integer n.Second line: n integers.Constraint: 1 ≤ n ≤ 100

Output format

text

Print YES if the values are sorted in non-decreasing order. Otherwise print NO.

Sample 1

Input

text

51 2 2 4 9

Output

text

YES

Sample 2

Input

text

43 1 2 4

Output

text

NO

Sample 3

Input

text

Output

text

YES

Sample 4

Input

text

4-5 -5 -2 0

Output

text

YES

Required structure

is_sorted.py

def is_sorted(a):    # TODO: return True if sorted, False otherwise    passn = int(input())a = list(map(int, input().split()))print("YES" if is_sorted(a) else "NO")

Hint: Compare neighboring values: a[i - 1] and a[i]. If the previous value is greater, the array is not sorted.

Check: For every problem, read the values into a Python list first. Still write the loop yourself even though list helpers exist.

— Homework 1 End —