变态跳台阶
变态跳台阶
http://www.nowcoder.com/questionTerminal/22243d016f6b47f2a6928b4313c85387
易知 f(n)=f(n-1)+f(n-2)+……f(1)+1
f(n-1)=f(n-2)+……f(1)+1
两式相减得f(n)=2f(n-1),同时应该考虑n=1的情况
public class Solution {
public int JumpFloorII(int target) {
return target<1?0:(target==1?1:1<<(target-1));
}
}
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