常见面试手写算法

import java.time.chrono.JapaneseChronology;

import java.util.Arrays;

public class Main {

public static int  binarySort(int[] number, int n) {

int start = 0;

int end = number.length – 1;

while(start <= end){

int middle = (start + end ) / 2;

if(number[middle] == n){

return middle;

}

if(number[middle] > n){

end = middle – 1;

}else{

start = middle + 1;

}

}

return -1;

}

    public static void quickSort(int[] number ,int start , int end) {

if(start < end){

int middle = getMiddle(number ,start, end);

quickSort(number, start, middle – 1);

quickSort(number, middle + 1, end);

}

}

private static int getMiddle(int[] number, int start, int end) {

int temp = number[start];

while(start < end){

while(end > start && number[end] > temp){

end –;

}

number[start] = number[end];

while(start < end && number[start] <= temp){

start ++;

}

number[end] = number[start];

}

number[start] = temp;

return start;

}

    public static void heapSort(int[] number) {

for(int i = number.length / 2  – 1; i >= 0; i–){

adjustHeap(number, i , number.length – 1);

}

for(int i = number.length – 1; i >= 0; i–){

int temp = number[i];

number[i] = number[0];

number[0] = temp;

adjustHeap(number, 0 , i – 1);

}

}

private static void adjustHeap(int[] number, int i, int end) {

int temp = number[i];

for(int j = 2 * i + 1; j < end; j = 2 * j + 1){

if(j < end && number[j] < number[j + 1] ){

j++;

}

if(temp >= number[j]){

break;

}

number[i] = number[j];

i = j;

}

number[i] = temp;

}

public static void mergeSort(int[] number, int low ,int high ) {

if(low < high){

int middle = (high + low ) / 2;

mergeSort(number, low, middle);

mergeSort(number, middle + 1, high);

merge(number, low , high);

}

}

private static void merge(int[] number, int low, int high) {

int[] temp = new int[high – low + 1];

int middle = (low + high) / 2;

int i = low;

int j = middle + 1;

int k = 0;

while(i <= middle && j <= high){

if(number[i] > number[j]){

temp[k++] = number[j++];

}else{

temp[k++] = number[i++];

}

}

while(i <= middle){

temp[k++] = number[i++];

}

while(j <= high){

temp[k++] = number[j++];

}

k = 0;

for(i = low ; i <= high; i++,k++){

number[i] = temp[k];

}

}

public static void main(String[] args) {

        int[] p = {1,2,3,5,9,7,8,9};

        mergeSort(p,0 ,p.length – 1);

        System.out.println(Arrays.toString(p));

}

    原文作者:宫羽卫-银飞羽
    原文地址: https://blog.csdn.net/dainandainan1/article/details/77851400
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