50分，一半tle

aishiteru_mitsu_ha @ 2024-03-07 17:51:33

#include<iostream>
using namespace std;
long long lt(long long n) {
    if (n == 1 || n == 0) {
        return 1;
    }
    return lt(n - 1) + lt(n - 2);
}
int main() {
    long long a;
    cin >> a;
    cout << lt(a);
    return 0;
}

by __Rickysun__ @ 2024-03-07 18:03:35

@not_much 这题是斐波那契数列，得用 dp ，当然，这种简单的 dp 其实就是地推，但是，由于 n<=5000 ， unsigned~long~long 来了也扛不住(bushi，所以得用亿点点高精度

by xk2013 @ 2024-03-07 18:08:09

@not_much 用递推啊 awa

by xk2013 @ 2024-03-07 18:18:08

@Rickysun unsigned __int128 行不？

by yuhaiyue @ 2024-03-23 11:23:21

用递推