# HackerRank ‘Gemstones’ Solution

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##### Short Problem Definition:

John has discovered various rocks. Each rock is composed of various elements, and each element is represented by a lower-case Latin letter from ‘a’ to ‘z’. An element can be present multiple times in a rock. An element is called a gem-element if it occurs at least once in each of the rocks.

Given the list of N rocks with their compositions, display the number of gem-elements that exist in those rocks.

Gemstones

##### Complexity:

time complexity is O(N*T)

space complexity is O(N)

##### Execution:

We count the number of elements that occur in all characters  sets. Just use set intersection.

##### Solution:
 1 2 3 4 5 6 7 8 9 `#!/usr/bin/py` `if` `__name__ ``=``=` `'__main__'``:` `    ``t ``=` `input``()` `    ``all_elements ``=` `set``(``raw_input``())` `    `  `    ``for` `_ ``in` `xrange``(t``-``1``):` `        ``all_elements &``=` `set``(``raw_input``())` `        `  `    ``print` `len``(all_elements)`

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