What is LeetCode 494 Target Sum?

Array nums, target S. Assign + or - to each. Count ways sum hits S.

How does DP solve LeetCode 494?

Pivot to subset sum: positives sum to (total + S)/2. 1D DP counts ways.

Is backtracking faster for Target Sum?

No. DP O(n*target) beats exponential backtrack.

LeetCode 494: Target Sum's Dirty DP Trick Exposed

LeetCode 494 boasts a 43% solve rate. That's thousands of devs flailing at assigning + or - to hit a target sum. Here's the DP subset sum pivot that actually works.

theAIcatchup Apr 09, 2026 3 min read

Visual DP array trace for LeetCode 494 Target Sum solution

⚡ Key Takeaways

Target Sum reduces to subset sum via (total + S)/2 — math pivot unlocks DP. 𝕏
Reverse loop in 1D DP prevents overcounting; backward from target to num. 𝕏
43% solve rate hides simple guards: parity and total >= |S|. 𝕏

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#Dynamic Programming #LeetCode #LeetCode 494 #algorithm visualization #algorithm-tracing #algorithm-visualizer #algorithms #subset-sum #target-sum

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Originally reported by dev.to

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