NeetCode #751LC-1269Hard2-D Dynamic Programming
← Back to All Problems#751 · #1269 · Number of Ways to Stay in the Same Place After Some Steps(停在原地的方案数)
📌 Problem Statement & Constraints
An array has length
arrLen and a pointer starts at index 0. Each step the pointer moves left, right, or stays put, and it must remain within [0, arrLen - 1]. Return the number of ways to be back at index 0 after exactly steps steps, modulo 1e9+7. Constraints: 1 <= steps <= 500, 1 <= arrLen <= 10^6.🔒
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