Jewels and Stones Python Solution with Tests

LeetCode 771, Easy. Topics: Hash Table, String. View on LeetCode. Generate this problem as a practice environment: tested reference solution, 20 parametrized pytest cases, and a playground notebook:

lcpy gen -n 771   # by problem number
lcpy gen -s jewels_and_stones   # by problem name

Problem

You’re given strings jewels representing the types of stones that are jewels, and stones representing the stones you have. Each character in stones is a type of stone you have. You want to know how many of the stones you have are also jewels. Letters are case sensitive, so "a" is considered a different type of stone from "A".

Examples

Input: jewels = "aA", stones = "aAAbbbb"
Output: 3

Input: jewels = "z", stones = "ZZ"
Output: 0

Constraints

1 <= jewels.length, stones.length <= 50
jewels and stones consist of only English letters.
All the characters of jewels are unique.

Solution

Reference implementation from solution.py on GitHub, full suite in test_solution.py:

class Solution:
    # Time: O(n + m)
    # Space: O(n)
    def num_jewels_in_stones(self, jewels: str, stones: str) -> int:
        jewel_set = set(jewels)
        return sum(stone in jewel_set for stone in stones)

Complexity

Time	Space
O(n + m)	O(n)

Welcome

Getting Started

Practice

CLI

Catalog

Contributing

Troubleshooting

Jewels and Stones Python Solution with Tests

Problem

Examples

Constraints

Solution

Complexity

Tags

​Problem

​Examples

​Constraints

​Solution

​Complexity

​Tags

Problem

Examples

Constraints

Solution

Complexity

Tags