Sword refers to offer-supplement 1. Jump up the stairs-analysis and code [Java]
1. Title
A frog can jump up to 1 step or 2 steps at a time. Find the total number of jumping methods the frog jumps on an n-level step (different order counts as different results).
Two, analysis and code
1. Dynamic programming
(1) Thinking
Dynamic programming basic problem, because you can jump 1 or 2 steps at a time, assuming that the number of steps to jump to the nth step is F(n), then F(n) = F(n-1) + F(n-2) .
The result is the Fibonacci sequence.
(2) Code
public class Solution {
public int JumpFloor(int target) {
if (target < 3)
return target;
int [] ans = new int[target];
ans[0] = 1;
ans[1] = 2;
for (int i = 2; i < target; i++)
ans[i] = ans[i - 1] + ans[i - 2];
return ans[target - 1];
}
}
(3) Results
Running time: 10 ms, occupying 9560 k of memory.
Three, other
Nothing.