William

Last seen: Today | Active since 2012

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Semi-retired physicist with interests in numerical modeling and mathematics.

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[Master Regular Expression] String To Integer
Implement the myAtoi(string s) function, which converts a string to a 32-bit signed integer. The algorithm for myAtoi(string s)...

18 hours ago

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Geometric Compression Ratio
The geometric compression ratio CR is the ratio of the total cylinder volume at BDC to the clearance volume at TDC. It is one of...

2 days ago

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Swept Volume and Clearance Volume
The swept volume (V_s) is the volume displaced by the piston as it travels from BDC (Bottom Dead Centre) to TDC (Top Dead Centre...

2 days ago

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Specific Fuel Consumption
Brake-specific fuel consumption (BSFC) measures how efficiently an engine converts fuel mass into useful work. Lower is better...

2 days ago

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Piston Mean Speed
Mean piston speed is a critical mechanical stress indicator — it sets limits on valve timing, bearing loads, and material fatigu...

2 days ago

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Engine Displacement
Engine displacement is the total swept volume of all cylinders. It is determined by bore (cylinder diameter), stroke (piston tra...

2 days ago

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Fuel-Air Equivalence Ratio (Lambda)
Lambda (λ) is the ratio of actual air-fuel ratio to the stoichiometric air-fuel ratio. λ = 1 is perfect stoichiometry, λ < 1 is ...

2 days ago

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Volumetric efficiency
Volumetric efficiency measures how well an engine breathes. The ratio of the actual air mass drawn in per cycle to the theoreti...

2 days ago

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Brake Mean Effective Pressure (BMEP)
BMEP is a normalised measure of engine work output per cycle per unit displacement. It lets you compare engines of different siz...

2 days ago

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Engine torque and RPM
Torque and power are related through rotational speed. Knowing brake power and engine RPM, you can back-calculate the torque del...

2 days ago

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Insert same number of zeros for each of elements in the vector. Number of zeros for a given number in vector
Same number of zeros for a given number in the vector, if there is a negative number in vector, then insert zeros to precede ...

2 days ago

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Engine Thermal Efficiency
The thermal efficiency of an ideal Otto cycle engine depends only on the compression ratio. A higher compression ratio yields gr...

2 days ago

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Given the ratio of the two legs (longer / shorter), and the hypotenuse length, find the shorter leg.
Further to the problem 43236, find the length of shorter leg P.S No built-in functions allowed

2 days ago

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Keep Only Even Numbers
Given a vector, return a new vector containing only the even numbers in their original order. Example: keep_evens([1 2 3 4 5 6])...

16 days ago

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Replace All Below-Average Elements in a Matrix with Zero
Given a 2D matrix of numbers, find the mean of all elements. Replace any element that is strictly below the mean with 0. Return ...

19 days ago

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Triangle Area Using Heron's Formula
Given the three side lengths a, b, and c of a triangle, calculate its area using Heron's formula and round to 4 decimal places. ...

19 days ago

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Count how many elements are above the mean
Given a vector, return the count of elements strictly greater than the mean of the vector. Example: above_mean_count([1 2 3 4 5]...

19 days ago

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Convert Celsius temperature to Fahrenheit
Given a temperature in Celsius, return the equivalent in Fahrenheit. Formula: F = C * 9/5 + 32Example: cel2fahr(100) returns 212...

19 days ago

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Count the vowels in a string
Given a string, return the number of vowels (a, e, i, o, u — case insensitive). Example: count_vowels('Hello World') returns 3

19 days ago

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Reverse the characters of a string
Given a string, return the string with characters in reverse order. Example: rev_string('hello') returns 'olleh'

19 days ago

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Sum the main diagonal of a matrix
Given a square matrix, return the sum of its main diagonal elements. Example: diag_sum([1 2 3; 4 5 6; 7 8 9]) returns 15

19 days ago

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Determine if a number is prime
Given a positive integer n, return 1 if it is prime, 0 otherwise. Example: is_prime(7) returns 1, is_prime(4) returns 0

19 days ago

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Robust Main Diagonal Sum with Special Value Handling in Arrays
Compute the sum of the diagonal elements of an array (vector or matrix). If array is not square return the char array: 'no-squa...

21 days ago

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Total Volume Goal ( Medium )
Usually, the target T must be in one jug. In this version, the target T is the sum of water in all N jugs. Example: C = [3,5], ...

23 days ago

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Record the Actions ( Medium )
Find the minimum steps to get T units from jugs A and B. Return the sequence of actions as cell array of strings. Available act...

24 days ago

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Electric Power Steering (EPS) Motor Torque with Efficiency
In EPS systems, the motor must generate additional torque to compensate for system losses. Given Required assist torque at rack...

25 days ago

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EPS Assist Map with respect to the Vehicle Speed
In Electric Power Steering (EPS), assist torque reduces as vehicle speed increases to improve stability at high speeds. Given S...

25 days ago

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Electric Power Steering (EPS) Assist Curve Calculation
Electric Power Steering (EPS) provides assist torque proportional to driver input. Given Steering torque Ts and Gain k, Compute...

25 days ago

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Steering Torque Estimation
Steering torque is generated due to lateral tire forces acting through the steering mechanism. Given Lateral force Fy and Lever...

25 days ago

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Understeer or Oversteer Gradient Calculation
This gradient determines whether a vehicle tends to understeer or oversteer. Given Mass m, Wheelbase L, Front cornering stiffne...

25 days ago