How should I practice Unit Conversion Across Independent Families?

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Unit Conversion Across Independent Families

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Problem statement

Each row in conversions is [source, target, rate] and means one unit of source equals rate units of target. A relationship may also be traversed backward using its reciprocal. Conversion families may be disconnected.

For every [from, to] query, return the product of rates along a conversion path, formatted with exactly six decimal places. Return UNKNOWN when either name does not appear or no path connects the two units. A known unit converted to itself is 1.000000.

Function

queryUnitConversions(conversions: String[][], queries: String[][]) → String[]

Examples

Example 1

conversions = [["C","F","1.8"],["m","cm","100"]]queries = [["C","F"],["F","C"],["C","cm"],["m","cm"]]return = ["1.800000","0.555556","UNKNOWN","100.000000"]

Temperature and length queries work within their own families, while a cross-family query is unknown.

Example 2

conversions = [["a","b","2"],["b","c","3"]]queries = [["a","c"],["c","a"],["b","b"]]return = ["6.000000","0.166667","1.000000"]

Path products, reciprocal traversal, and identity queries share one component.

Constraints

0 <= conversions.length, queries.length <= 100000.
Rates are positive decimal strings.
All relationships are mutually consistent, so every path between the same pair has the same product.
Unit names are nonempty and contain no spaces.