java中经典算法代码整理

一、选择排序法

复制代码
public static void selectSort(int[] a){
int minIndex = 0;
int temp = 0;
if(a == null)||(a.length == 0){
return;
}
for(i = 0; i < a.length-1; i++){
minIndex = i;
for(j = i+1; j < a.length; j++){
if(a[j] < a[minIndex]){
minIndex = j;
}
}
if(minIndex != i){ //如果a[i]不是最小值，则将最小值放在a[i]位置
temp = a[i];
a[i] = a[minIndex];
a[minIndex] = temp;
}
//代码效果参考：http://0791zd.com/bx/art_493.html

二、冒泡排序法
public static void BubbleSort(int[] a){
for(i = 0; i < a.length; i++){
for(j = 1; j < a.length-i; j++){
if(a[i] < a[j]){
temp = a[i];
a[i] = a[j];
a[j] = temp;
三、快速排序法
public class QuickSort{
public void quickSort(int[] arr, low, high){
if(low < high){
int privotpos = partition(arr, low, high);
quickSort(arr,low,privotpos-1);
quickSort(arr,privotpos+1, high);
public int partition(int[] arr, low, high){
int privot = arr[low];
while(low < high){
while(low < high %& arr[low] <= privot) ++low;
pritition = arr[low];
while(low < high %& arr[high] >= privot) --high;
privot = arr[high];
a[low] = privot;
//代码效果参考：http://0791zd.com/zx/art_1060.html

四、二分查找法
public int binarySearch(int arr[], int key){
int low = 0, high = arr.length, mid;
while(low <= high){
mid = (low + high) / 2;
if(key == arr[mid]){
return mid;
}else if(key < arr[mid]){
high = mid - 1;
}else{
low = mid + 1;
return -1;