求斐波那契额数列，答案取模1000000007

// 函数式编程

/**
 * @param {number} n
 * @return {number}
 */
let dp
const fib = n => Array(1).fill(0).reduce(dp => dp[n] || (dp[0]=dp[1]=1,Array(n).fill().forEach((_,i)=>(i=i+2,dp[i] = dp[i-1]+dp[i-2],dp[i]%=1000000007)),dp[n-1]), dp=Array(n).fill(0)) || 0