【万人千题计划】刷题报告11.17

1，斐波那契数列leetcode509

int fib(int n)
{
    int fin;
    if(n<=1)
    return n;
    if(n==2)
     return n-1; 
     else
     {
        int a=1;
        int b=1;
        int c;
        while(n-2)
        {
            c=a+b;
            a=b;
            b=c;
            n--;
        }
        fin=c;
     }
    return fin;
}

2,leetcode1137，第n个泰波那契数

int tribonacci(int n)
{
    int fin;
     if(n<=1)
     return n;
     if(n==2)
     return n-1;
     else
     {
         int d;
         int a=0;
            int b=1;
            int c=1;
        while(n-2)
        {
            d=a+b+c;
            a=b;
            b=c;
            c=d;
            n--;
        }
        fin=d;
     }
     return fin;
}