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Competitive Programming Academy · Lesson

Climbing Stairs & Coin Combinations

Classic 1D recurrences from scratch.

Meet Climbing Stairs

You can take 1 or 2 steps at a time. How many ways reach step n? This classic 1D DP is just Fibonacci in disguise.

Find the Recurrence

To stand on step i you came from i-1 or i-2. So dp[i] = dp[i-1] + dp[i-2], summing both last moves.

dp[i] = dp[i-1] + dp[i-2]

All lessons in this course

  1. Memoization vs Tabulation
  2. Define State and Transition
  3. Climbing Stairs & Coin Combinations
  4. Longest Increasing Subsequence
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