[HNU 10072] Fibonacci Number

kikook發表於2020-12-21
Fibonacci Number
Time Limit: 1000ms, Special Time Limit:2500ms, Memory Limit:32768KB
Total submit users: 2105, Accepted users: 1749
Problem 10072 : No special judgement
Problem description
The Fibonacci Numbers {0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, ...} are defined by the recurrence:
F0 = 0
F1 = 1
Fi = Fi-1 + Fi-2 for all i >= 2
Write a program to calculate the Fibonacci Numbers.
 
Input
The first line of the input file contains a single integer T, the number of test cases. The following T lines, each contains an integer n ( 0 <= n <= 45 ), and you are expected to calculate Fn.
 
Output
Output Fn on a separate line.
 
Sample Input
5
0
3
5
9
20
Sample Output
0
2
5
34
6765
Problem Source
SJTU2004

AC:

#define _CRT_SECURE_NO_WARNINGS
#include <cstdio>

inline void read(int& n)
{
    char ch = getchar(); n = 0;
    while (ch < '0' || ch > '9') { ch = getchar(); }
    while (ch >= '0' && ch <= '9') { n = (n << 1) + (n << 3) + ch - '0';  ch = getchar(); }
}

long long fi(int n)
{
    int a[] = { 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55 };
    if (n <= 10) return a[n];
    long long a9 = 34, a10 = 55, s;
    for (int i = 11; i <= n; ++i)
    {
        s = a9 + a10;
        a9 = a10; a10 = s;
    }
    return s;
}

int main()
{
    int n, m;
    read(n);
    for (int i = 0; i < n; ++i)
    {
        read(m);
        printf("%lld\n", fi(m));
    }
    return 0;
}

 

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