pat乙级练习题 客似云来

代码

#include<iostream>
using namespace std;

long long F[81];

int main(){
    int from,to;
    F[1] = F[2] = 1;
    while(scanf("%d%d",&from,&to) != EOF){
        for(int i = 3;i <= to;i++)
            F[i] = F[i - 1] + F[i - 2];
        long long res = 0;
        for(int i = from;i <= to;i++)
            res += F[i];
        cout<<res<<endl;
    }
    return 0;
}