Beginner
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LEVEL:Beginner
Description
A child is running up a staircase with n steps and can hop either 1 step, 2 steps, or 3 steps at a time. Implement a method to count how many possible ways the child can run up the stairs.
Input Format
A single integer n denoting number of steps.
Output Format
Total no. of ways child can run up.
4
7
3
4
10
274
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Approach
This was a recursion problem. But recursion took time, so dynamic programming can be applied using the steps named list. No. of steps for a number n can be determined by n-1, n-2, n-3. All the results were calculated by the formula and stored for later use. So that again and again already calculated values need not be calculated again.
Note :
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