如何解决指向结构体的数据结构
我想从头开始构建一个指向 C++ 结构的优先级队列。我知道这可以通过 priority_queue <struct_name> pq
使用 STL 库轻松完成。但是,我有兴趣使用数组自己构建它。我最初的方法是为整数构建一个最小堆,并最终修改代码使数组指向一个结构。为了给你更多的上下文,这是我到目前为止编写的代码。
#include<iostream>
#define MAX_SIZE 100
using namespace std;
struct cell{
int x,y;
int depth;
// Constructor
cell(int x,int y,int depth):
x(x),y(y),depth(depth) {}
};
class minHeap{
private:
// Current size of heap
int size;
// Max size of heap
int capacity;
// Storing elements as an array
struct cell* heap = new struct cell[MAX_SIZE];
// Returns the parent index
int parent(int i){
return (i-1)/2;
}
// Returns left child
int leftChild(int i){
return 2*i + 1;
}
// returns right child
int rightChild(int i){
return 2*i + 2;
}
public:
// Constructor
minHeap(int capacity){
size = 0;
this->capacity = capacity;
}
void insert(struct cell node){
if(size == capacity){
cout<<"Heap is FULL"<<endl;
return;
}
// Increase the amount of elements in the heap
size++;
// Insert the element at the end of heap
heap[size-1] = node;
// Maintain heap invariance
int i = size - 1;
while(i!=0 && greater(heap[parent(i)],heap[i])){
struct cell temp = heap[i];
heap[i] = heap[parent(i)];
heap[parent(i)] = temp;
i = parent(i);
}
}
void heapify(int i){
int left = leftChild(i);
int right = rightChild(i);
int smallest = i;
// Find the smallest element of the three
if((left < size) && greater(heap[left],heap[smallest])){
smallest = left;
}
if((right < size) && (greater(heap[right],heap[smallest]))){
smallest = right;
}
// If the smallest is left or right,keep heapifying
if(smallest != i){
struct cell temp = heap[i];
heap[i] = heap[smallest];
heap[smallest] = temp;
heapify(smallest);
}
}
int extractMin(){
// Check is heap is empty
if(size == 0){
cout<<"Heap is empty"<<endl;
return -1;
}
else if(size == 1){
size--;
return heap[0].depth;
}
else{
struct cell root = heap[0];
heap[0] = heap[size-1];
size--;
heapify(0);
return root.depth;
}
}
void printHeap(){
int power = 0;
int value = 0;
for(int i=0; i<size; i++){
if(i == value){
cout<<endl;
power += 1;
value += (1<<power);
}
cout<<heap[i].depth<<" ";
}
cout<<endl;
}
};
bool greater(struct cell cell1,struct cell cell2){
if(cell1.depth == cell2.depth){
if(cell1.x != cell2.depth){
return (cell1.x < cell2.x);
}
else return cell1.y < cell2.y;
}
return cell1.depth < cell2.depth;
}
int main(){
minHeap m1(15);
return 0;
}
但是,我在执行此操作后遇到了一些错误。我在下面列出了它们:
Heap.cpp:24:46: error: no matching function for call to 'cell::cell()'
struct cell* heap = new struct cell[MAX_SIZE];
^
Heap.cpp:11:2: note: candidate: cell::cell(int,int,int)
cell(int x,int depth):
^~~~
Heap.cpp:11:2: note: candidate expects 3 arguments,0 provided
Heap.cpp:6:8: note: candidate: constexpr cell::cell(const cell&)
struct cell{
^~~~
Heap.cpp:6:8: note: candidate expects 1 argument,0 provided
Heap.cpp:6:8: note: candidate: constexpr cell::cell(cell&&)
Heap.cpp:6:8: note: candidate expects 1 argument,0 provided
Heap.cpp: In member function 'void minHeap::insert(cell)':
Heap.cpp:59:24: error: missing template arguments before '(' token
while(i!=0 && greater(heap[parent(i)],heap[i])){
^
Heap.cpp: In member function 'void minHeap::heapify(int)':
Heap.cpp:73:30: error: missing template arguments before '(' token
if((left < size) && greater(heap[left],heap[smallest])){
^
Heap.cpp:76:32: error: missing template arguments before '(' token
if((right < size) && (greater(heap[right],heap[smallest]))){
我对 C++ 比较陌生,所以我不确定我是否提供了所有必要的信息。如果我能提供任何其他详细信息,请告诉我。
解决方法
因为单元格有一个带参数的构造函数,但没有列出默认(无参数)构造函数,所以你会得到第一个错误。
您要么需要创建一个默认构造函数,要么使您拥有的构造函数的参数采用默认值。
解决这个问题,看看有多少其他错误消失了。
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