求java实现C语言常用算法的程序(如各种排序算法),以及Java考题

2024-11-23 08:45:35
推荐回答(3个)
回答(1):

Java 算法:
public class Sort {

public void swap(int a[], int i, int j) {
int tmp = a[i];
a[i] = a[j];
a[j] = tmp;
}

public int partition(int a[], int low, int high) {
int pivot, p_pos, i;
p_pos = low;
pivot = a[p_pos];
for (i = low + 1; i <= high; i++) {
if (a[i] > pivot) {
p_pos++;
swap(a, p_pos, i);
}
}
swap(a, low, p_pos);
return p_pos;
}

public void quicksort(int a[], int low, int high) {
int pivot;
if (low < high) {
pivot = partition(a, low, high);
quicksort(a, low, pivot - 1);
quicksort(a, pivot + 1, high);
}

}

public static void main(String args[]) {
int vec[] = new int[] { 37, 47, 23, -5, 19, 56 };
int temp;
//选择排序法(Selection Sort)
long begin = System.currentTimeMillis();
for (int k = 0; k < 1000000; k++) {
for (int i = 0; i < vec.length; i++) {
for (int j = i; j < vec.length; j++) {
if (vec[j] > vec[i]) {
temp = vec[i];
vec[i] = vec[j];
vec[j] = temp;
}
}

}
}
long end = System.currentTimeMillis();
System.out.println("选择法用时为:" + (end - begin));
//打印排序好的结果
for (int i = 0; i < vec.length; i++) {
System.out.println(vec[i]);
}
// 冒泡排序法(Bubble Sort)
begin = System.currentTimeMillis();
for (int k = 0; k < 1000000; k++) {
for (int i = 0; i < vec.length; i++) {
for (int j = i; j < vec.length - 1; j++) {
if (vec[j + 1] > vec[j]) {
temp = vec[j + 1];
vec[j + 1] = vec[j];
vec[j] = temp;
}
}

}
}
end = System.currentTimeMillis();
System.out.println("冒泡法用时为:" + (end - begin));
//打印排序好的结果
for (int i = 0; i < vec.length; i++) {
System.out.println(vec[i]);
}

//插入排序法(Insertion Sort)
begin = System.currentTimeMillis();
for (int k = 0; k < 1000000; k++) {
for (int i = 1; i < vec.length; i++) {
int j = i;
while (vec[j - 1] < vec[i]) {
vec[j] = vec[j - 1];
j--;
if (j <= 0) {
break;
}
}
vec[j] = vec[i];
}
}
end = System.currentTimeMillis();
System.out.println("插入法用时为:" + (end - begin));
//打印排序好的结果
for (int i = 0; i < vec.length; i++) {
System.out.println(vec[i]);
}

//快速排序法(Quick Sort)

Sort s = new Sort();
begin = System.currentTimeMillis();
for (int k = 0; k < 1000000; k++) {
s.quicksort(vec, 0, 5);
}
end = System.currentTimeMillis();
System.out.println("快速法用时为:" + (end - begin));
//打印排序好的结果
for (int i = 0; i < vec.length; i++) {
System.out.println(vec[i]);
}
}

}
以下是运行结果:
选择法用时为:234
56
47
37
23
19
-5
冒泡法用时为:172
56
47
37
23
19
-5
插入法用时为:78
56
47
37
23
19
-5
快速法用时为:297
56
47
37
23
19
-5

回答(2):

给你写个简单的冒泡算法:

public class MaoPao {
public static void main(String[] args) {
int[] st={12,34,9,31,27,42,33,19};
for(int i=0;i for(int j=0;j if(st[j]>st[j+1]){
int temp=st[j];
st[j]=st[j+1];
st[j+1]=temp;
}
}
}
for(int s : st){
System.out.print(s+" , ");
}
}

}

回答(3):

建议你去找本java的算法与数据结构,电子书免费的,里面什么都有