Floor and Ceil in Sorted Array in DSA Go - Practice Problems & Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Find floor and ceil of 7 in a sorted array

Given the sorted array [1, 3, 5, 7, 9], what is the floor and ceil of 7?

DSA Go

arr := []int{1, 3, 5, 7, 9}
num := 7
floor, ceil := -1, -1
for _, v := range arr {
    if v <= num {
        floor = v
    }
    if v >= num && ceil == -1 {
        ceil = v
    }
}
fmt.Printf("Floor: %d, Ceil: %d", floor, ceil)

A Floor: 5, Ceil: 7

B Floor: 7, Ceil: 9

C Floor: 7, Ceil: 7

D Floor: 5, Ceil: 9

💡 Hint

Floor is the greatest element less than or equal to the number; ceil is the smallest element greater than or equal to the number.

Since 7 is present in the array, both floor and ceil are 7.

❓ Predict Output

intermediate

Floor and ceil for a number not in the array

What is the floor and ceil of 6 in the sorted array [1, 3, 5, 7, 9]?

DSA Go

arr := []int{1, 3, 5, 7, 9}
num := 6
floor, ceil := -1, -1
for _, v := range arr {
    if v <= num {
        floor = v
    }
    if v >= num && ceil == -1 {
        ceil = v
    }
}
fmt.Printf("Floor: %d, Ceil: %d", floor, ceil)

A Floor: 7, Ceil: 9

B Floor: 5, Ceil: 7

C Floor: 5, Ceil: 6

D Floor: 6, Ceil: 7

💡 Hint

Floor is the greatest element less than or equal to the number; ceil is the smallest element greater than or equal to the number.

6 is not in the array. The greatest element less than 6 is 5 (floor), and the smallest element greater than 6 is 7 (ceil).

🧠 Conceptual

advanced

Behavior when number is smaller than all elements

If the number is smaller than all elements in a sorted array, what will be the floor and ceil?

A Floor: -1 (no floor), Ceil: smallest element in array

B Floor: smallest element, Ceil: -1 (no ceil)

C Floor and Ceil both are -1

D Floor and Ceil both are the smallest element

💡 Hint

Floor must be less than or equal to the number; if none exists, floor is -1.

If the number is smaller than all elements, no floor exists (-1), but ceil is the smallest element.

🧠 Conceptual

advanced

Floor and ceil when number is greater than all elements

If the number is greater than all elements in a sorted array, what will be the floor and ceil?

A Floor: largest element in array, Ceil: -1 (no ceil)

B Floor: -1 (no floor), Ceil: largest element

C Floor and Ceil both are largest element

D Floor and Ceil both are -1

💡 Hint

Ceil must be greater than or equal to the number; if none exists, ceil is -1.

If the number is greater than all elements, floor is the largest element, but no ceil exists (-1).

🔧 Debug

expert

Identify the error in floor and ceil calculation code

What error does the following Go code produce when finding floor and ceil? arr := []int{2, 4, 6, 8} num := 5 floor, ceil := -1, -1 for _, v := range arr { if v < num { floor = v } if v > num && ceil == -1 { ceil = v } } fmt.Printf("Floor: %d, Ceil: %d", floor, ceil)

DSA Go

arr := []int{2, 4, 6, 8}
num := 5
floor, ceil := -1, -1
for _, v := range arr {
    if v < num {
        floor = v
    }
    if v > num && ceil == -1 {
        ceil = v
    }
}
fmt.Printf("Floor: %d, Ceil: %d", floor, ceil)

A Floor: -1, Ceil: 6

B Floor: 5, Ceil: 6

C Floor: 4, Ceil: -1

D Floor: 4, Ceil: 6

💡 Hint

Check the comparison operators used for floor and ceil conditions.

The code uses '<' and '>' which exclude equality. Since 5 is not in the array, floor is the greatest element less than 5 (4), and ceil is the smallest element greater than 5 (6).