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This is a medium difficulty Coding & Algorithms question, commonly asked during Technical Screen rounds at Walmart Labs.

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This question is commonly asked for Software Engineer candidates at Walmart Labs during technical interviews.

Count ways to make change (DP) | Walmart Labs Interview Question

Q: Count ways to make change (DP)

This question evaluates understanding of dynamic programming and combinatorial counting, focusing on unbounded coin usage and counting order‑independent combinations.

Problem

You are given an integer amount and an array of positive, distinct integers coins, where each coin value can be used unlimited times.

Return the number of distinct combinations of coins that sum to exactly amount.

Notes:

The order does not matter . For example, 2+1 and 1+2 are the same combination.
If amount = 0 , there is exactly one way: choose no coins.

Input/Output

Input: integer amount , integer array coins
Output: integer ways

Examples

amount = 5, coins = [1,2,5] → 4
- Combinations: 5 , 2+2+1 , 2+1+1+1 , 1+1+1+1+1
amount = 3, coins = [2] → 0
amount = 0, coins = [1,2] → 1

Constraints (assume)

0 ≤ amount ≤ 10^4
1 ≤ len(coins) ≤ 300
Result fits in 64-bit signed integer

Problem

You are given an integer amount and an array of positive, distinct integers coins, where each coin value can be used unlimited times.

Return the number of distinct combinations of coins that sum to exactly amount.

Notes:

The order does not matter . For example, 2+1 and 1+2 are the same combination.
If amount = 0 , there is exactly one way: choose no coins.

Input/Output

Input: integer amount , integer array coins
Output: integer ways

Examples

amount = 5, coins = [1,2,5] → 4
- Combinations: 5 , 2+2+1 , 2+1+1+1 , 1+1+1+1+1
amount = 3, coins = [2] → 0
amount = 0, coins = [1,2] → 1

Constraints (assume)

0 ≤ amount ≤ 10^4
1 ≤ len(coins) ≤ 300
Result fits in 64-bit signed integer

Count ways to make change (DP)

Quick Overview

Problem

Input/Output

Examples

Constraints (assume)

Submit Your Answer

Count ways to make change (DP)

Quick Overview

Problem

Input/Output

Examples

Constraints (assume)

Submit Your Answer