AP CSP Topic 3.9 Coding Practice - Developing Algorithms
Big Idea 3: Algorithms and Programming · Topic 3.9 · Coding Practice
Developing Algorithms — Code It Yourself
Write real code and check it against the expected output. Pick Python or JavaScript; the AP pseudocode reference is there when you need it.
You warmed these up on paper in Trace and Compare and Build It from Blocks, using the Level Up game. Now type and run them for real — same building blocks, harder each time. The first is a straight building block; the last you assemble and modify yourself. Predict the output first, then check it.
Problem 1 of 4
Building block — MAX. Two players scored 88 and 95. Print the higher score.
Expected output: 95
Show AP pseudocode reference
a ← 88
b ← 95
IF(a > b) { higher ← a } ELSE { higher ← b }
DISPLAY(higher)
Compare a and b with an IF/ELSE: if a > b the higher is a, otherwise it is b. Print that value.
Problem 2 of 4
Building block — DIVISIBILITY. A coin appears on every 3rd tile. For tile = 12, print coin if 3 divides it evenly, otherwise print no coin.
MOD (written % in Python and JavaScript) gives the remainder. A remainder of 0 means the division is exact, so 3 divides the tile evenly.
Problem 3 of 4
Combine blocks — AVERAGE, then PASS/FAIL. Three playtesters scored 80, 90, and 100. Compute their average, then print pass if the average is at least 60, otherwise fail.
This combines two building blocks: first the average (add the three scores, divide by 3), then a comparison (is the average >= 60?). Compute the average into its own variable, then test it.
Problem 4 of 4
Modify + build — MIN of three. Starting from the find-max idea, write an algorithm that prints the smallest of three scores: 88, 72, 95.
Expected output: 72
Show AP pseudocode reference
a ← 88
b ← 72
c ← 95
smallest ← a
IF(b < smallest) { smallest ← b }
IF(c < smallest) { smallest ← c }
DISPLAY(smallest)
Take the two-number min and extend it: assume the first is smallest, then compare it against each other value with <, updating smallest whenever you find a lower one. This is the max building block modified (> became <) and extended to three.
Your code runs on a secure external service. Answers are checked automatically — nothing is stored.
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