Three ways to implement Fibonacci numbers in JS

The following is the javascript basic introduction tutorial column to introduce to you three methods of realizing Fibonacci series in JS. I hope it will be helpful to friends in need!

Three ways to implement Fibonacci numbers in JS

How do you implement Fibonacci numbers?

1,1,2,3,5,8...

f(n)=f(n-1) f(n-2)

Method 1:

function f(n){
    if(n == 1 || n == 0){
        return 1;
    }
    return f(n-1) + f(n-2);
}

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Here are two more solutions for comparison

Method 2:

function f(n) {
    var arr = [];
    var value = null;

    function _f(n) {
        if (n == 1 || n == 0) {
        return 1;
    }
    if (arr[n])
        return arr[n];
        value = _f(n - 1) + _f(n - 2);
        arr[n] = value;
        return value;
    }
    return _f(n);
}        

方法二

There is also a simpler solution Array storage is used

Method three:

function fn(n) {
     var dp = new Array(n + 1);
     dp[0] = dp[1] = 1;
     for (let i = 2, length = dp.length; i < length; i++) {
          dp[i] = dp[i - 1] + dp[i - 2];
     }
     return dp[n];
}

Related recommendations: "javascript Advanced Tutorial"

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