快速排序和二分查找(Java)

import java.util.Arrays;

public class Main {

public static void main(String[] args) {

int[] data = {2, 3, 5, 1, 4, 5, 2, 13, 51, 9, 10, 15, 17, 6, 21, 33, 44, 77, 22};

System.out.println(Arrays.toString(data));        quickSort(data, 0, data.length - 1);        System.out.println(Arrays.toString(data));        int index = binarySearch(data, 4);        System.out.println(index);    }

private static int partition(int[] data, int left, int right) {        int i = left;        int j = right;        //pivot        int pivot = data[left + (right - left) / 2];        //完成一趟排序        while (i <= j) {            //从右往左找到第一个小于pivot的数            while (data[j] > pivot) {                j--;            }            //从左往右找到第一个大于pivot的数            while (data[i] < pivot) {                i++;            }            //交换            if (i <= j) {                int p = data[i];                data[i] = data[j];                data[j] = p;                i++;                j--;            }        }

return i;    }

public static void quickSort(int[] data, int left, int right) {

int index = partition(data, left, right);

if (left < index - 1) {            quickSort(data, left, index - 1);        }

if (index < right) {            quickSort(data, index, right);        }    }

public static int binarySearch(int[] data, int target) {        int left = 0, right = data.length - 1;        while (left <= right) {            int mid = left + (right - left) / 2;            if (data[mid] < target) {                left = mid + 1;            }            if (data[mid] >= target) {                right = mid - 1;            }        }        return left;    }

public int binarySearchRecur(int[] data, int target, int left, int right) {        if (left > right) {            return left;        }        int mid = left + (right - left) / 2;        if (data[mid] < target) {            return binarySearchRecur(data, target, mid + 1, right);        } else {            return binarySearchRecur(data, target, left, mid - 1);        }    }

}

原文地址：https://www.cnblogs.com/feicheninfo/p/9283338.html