DSA · Theory

Weighted Prefix Search

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Theory

496/810

Weighted Prefix Search

Weighted Prefix Search is a DSA idea you prove with find roll 12, not with a slogan.

Keep Weighted Prefix Search small. Dev should finish find roll 12 in a few lines, not a 40-line dump.

Skip Weighted Prefix Search and binary search on unsorted data shows up in a sorted list.

Use Weighted Prefix Search when find roll 12 must stay clear. If a simpler DSA step works, use that instead.

Don’t do this with Weighted Prefix Search: binary search on unsorted data. Interviewers spot it in ten seconds.

After Weighted Prefix Search, Dev should still remember binary search on unsorted data.

Close Weighted Prefix Search with — “If I skip it, find roll 12 goes wrong like this: binary search on unsorted data.”

Exam tip

Say Weighted Prefix Search in one breath, then linear vs binary, then binary search on unsorted data.

Example

# Weighted Prefix Search
data = [4, 1, 3]
print("start", data)
if data[0] > data[1]:
    data[0], data[1] = data[1], data[0]
print("after one step", data)

Weighted Prefix Search: dry-run [4, 1, 3]. Say the list after one step.

Short notes

DefWeighted Prefix Search — Dev uses it for find roll 12 in a sorted list.
RuleWeighted Prefix Search → linear vs binary.
RememberWeighted Prefix Search + a dry-run table (a sorted list).
UseWeighted Prefix Search in a sorted list (find roll 12).
TrapWeighted Prefix Search — binary search on unsorted data.
ExWeighted Prefix Search → find roll 12.

DSA · Theory

Weighted Prefix Search

← All stacks

Theory

496/810

Weighted Prefix Search

Weighted Prefix Search is a DSA idea you prove with find roll 12, not with a slogan.

Keep Weighted Prefix Search small. Dev should finish find roll 12 in a few lines, not a 40-line dump.

Skip Weighted Prefix Search and binary search on unsorted data shows up in a sorted list.

Use Weighted Prefix Search when find roll 12 must stay clear. If a simpler DSA step works, use that instead.

Don’t do this with Weighted Prefix Search: binary search on unsorted data. Interviewers spot it in ten seconds.

After Weighted Prefix Search, Dev should still remember binary search on unsorted data.

Close Weighted Prefix Search with — “If I skip it, find roll 12 goes wrong like this: binary search on unsorted data.”

Exam tip

Say Weighted Prefix Search in one breath, then linear vs binary, then binary search on unsorted data.

Example

# Weighted Prefix Search
data = [4, 1, 3]
print("start", data)
if data[0] > data[1]:
    data[0], data[1] = data[1], data[0]
print("after one step", data)

Weighted Prefix Search: dry-run [4, 1, 3]. Say the list after one step.

Short notes

DefWeighted Prefix Search — Dev uses it for find roll 12 in a sorted list.
RuleWeighted Prefix Search → linear vs binary.
RememberWeighted Prefix Search + a dry-run table (a sorted list).
UseWeighted Prefix Search in a sorted list (find roll 12).
TrapWeighted Prefix Search — binary search on unsorted data.
ExWeighted Prefix Search → find roll 12.

Weighted Prefix Search

Example

Short notes

Questions

Weighted Prefix Search

Example

Short notes

Questions