带备忘的斐波那契算法

public static int fib(int n){int[] arr = new int[n+1];return fib(n,arr);}public static int fib(int n, int[] arr){if(n==1){arr[1]=1;return arr[1];}else if(n==2){arr[2]=1;return arr[2];}else {if(arr[n]!=0) return arr[n];int s = fib(n-1,arr)+fib(n-2,arr);arr[n] = s;return arr[n];}}