跳台阶进阶

题目描述: 一个台阶总共有 n 级,如果一次可以跳 1 级,也可以跳 2 级……也可以跳 n 级,求跳到 n 阶台阶有多少种跳法。

显而易见,当n = 1时,Fib(1) = 1;当n = 2时,Fib(2) = 2;

当n = 3时,Fib(3) = Fib(1) + Fib(2) + 1 = 4;

当n = 4时,Fib(4) = Fib(1) + Fib(2) + Fib(3) + 1 = 8;

当n = 5时,Fib(5) = Fib(1) + Fib(2) + Fib(3) + Fib(4) + 1 = 16;

当n = 6时,Fib(6) = Fib(1) + Fib(2) + Fib(3) + Fib(4) + Fib(5) + 1 = 32;

......

规律可得:

Fib(n - 1) = Fib(1) + Fib(2) + ....... + Fib(n - 2) + 1;

Fib(n) = Fib(1)+Fib(2)+.......+ Fib(n - 2) + Fib(n - 1) + 1;

则,Fib(n) = Fib(n - 1) + Fib(n - 1) = 2 * Fib(n - 1);

AC代码:

#include<iostream>
#include<string>
#include<algorithm>
#include<queue>
#include<set>
#include<stack>

using namespace std;

int n;
int t;
long long nums[35];

void init() {
    nums[1] = 1;
    nums[2] = 2;

    for(int i = 3; i <= 35; ++i) {
        nums[i] = 2 * nums[i - 1];
    }
}

int main() {

    cin >> t;
    init();
    while(t--) {
        cin >> n;
        cout << nums[n] << endl;
    }
    return 0;
}

results matching ""

    No results matching ""