Java实现常用算法

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Javacollections已经内置了一些常用算法，此处作为标记，方便温故而知新

1、二分查找

public class BinarySearch {    public static <T> int binarySearch(List<? extends Comparable<? super T>> list, T data) {        int start = 0;        int end = list.size() - 1;        while (start <= end) {            int mid = (end + start) >>> 1;            Comparable<? super T> midVal = list.get(mid);            if (midVal.compareTo(data) == 0) {                return mid;            } else if (midVal.compareTo(data) > 0) {                end = mid - 1;            } else {                start = mid + 1;            }        }        return -1;    }    public static void main(String[] args) {        int i = binarySearch(Arrays.asList(1, 2, 3, 6, 8, 44, 99, 145), 18);        System.out.println(i);    }}

2、斐波拉契数列（Fibonacci），除第一个和第二个数外，任意一个数都可由前两个数相加得到

public class FibonacciDemo {    public static ArrayList<Integer> fib(int size) {        int a = 0;        int b = 1;        //中间结果标记        int n = 0;        //数组长度计数器        int len = 0;        ArrayList<Integer> nums = new ArrayList<>();        while (len <= size) {            len++;            n = a + b;            nums.add(n);            a = b;            b = n;        }        return nums;    }    public static void main(String[] args) {        ArrayList<Integer> fibList = fib(10);        System.out.println(fibList);    }}

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