Java 如何实现合并排序?
我试图实现一个递归mergesort,但该方法只在排序向量中写入零。这是我的密码。在main函数中,我只是将值读入一个向量,并将其作为参数传递给mergesort。你知道我做错了什么吗?多谢各位Java 如何实现合并排序?,java,sorting,mergesort,Java,Sorting,Mergesort,我试图实现一个递归mergesort,但该方法只在排序向量中写入零。这是我的密码。在main函数中,我只是将值读入一个向量,并将其作为参数传递给mergesort。你知道我做错了什么吗?多谢各位 public static void mergesort(int [] v){ int mid=v.length/2; if( v.length < 2) return; int l[]=new int [mid]; int r[] = new int [v.length-mid];
public static void mergesort(int [] v){
int mid=v.length/2;
if( v.length < 2)
return;
int l[]=new int [mid];
int r[] = new int [v.length-mid];
for(int i=0; i<mid-1; i++)
l[i]=v[i];
for(int i=mid; i<v.length-1; i++)
r[i-mid]=v[i];
mergesort(l);
mergesort(r);
mergesort(l,r,v);
}
public static void mergesort(int [] l, int [] r, int [] v){
int i=0, j=0, k=0;
while(i< l.length && j< r.length){
if(l[i] <= r[j]){
v[k]=l[i];
i++;
}
else{
v[k]=r[j];
j++;
}
k++;
}
while(i < l.length){
v[k]=l[i];
i++;
k++;
}
while(j< r.length){
v[k]=r[j];
j++;
k++;
}
}
publicstaticvoidmergesort(int[]v){
int mid=v.length/2;
如果(v.长度<2)
返回;
int l[]=新int[mid];
int r[]=新int[v.length-mid];
对于(int i=0;i,算法中有两个错误
错误1:
while (i < r.length && j < r.length) {
if (l[i] <= r[j]) {
v[k] = l[i];
i++;
} else {
v[k] = r[j];
j++;
}
k++;
}
while(i 如果(l[i]假设您输入一个大小为2的向量,那么根据您的代码
mid=1;
for(int i=0;i<mid-1;i++)
// here i < (1-1) which will never execute
l[i]=v[i];
mid=1;
对于(int i=0;i
for (int i = 0; i <= mid - 1; i++)
l[i] = v[i];
for (int i = mid; i <= v.length - 1; i++)
r[i - mid] = v[i];
public static void mergesort(int [] v) {
int mid = v.length / 2;
if ( v.length < 2)
return;
int l[] = new int [mid];
int r[] = new int [v.length - mid];
for (int i = 0; i <= mid - 1; i++)
l[i] = v[i];
for (int i = mid; i <= v.length - 1; i++)
r[i - mid] = v[i];
mergesort(l);
mergesort(r);
mergesort(l, r, v);
}
public static void mergesort(int [] l, int [] r, int [] v) {
int i = 0, j = 0, k = 0;
while (i < l.length && j < r.length) {
if (l[i] <= r[j]) {
v[k] = l[i];
i++;
} else {
v[k] = r[j];
j++;
}
k++;
}
while (i < l.length) {
v[k] = l[i];
i++;
k++;
}
while (j < r.length) {
v[k] = r[j];
j++;
k++;
}
}
mid=1;
for(int i=0;i<mid-1;i++)
// here i < (1-1) which will never execute
l[i]=v[i];