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PTA Percolate Up and Down
Write the routines to do a "percolate up" and a "percolate down" in a binary min-heap.
Format of functions:
void PercolateUp( int p, PriorityQueue H );
void PercolateDown( int p, PriorityQueue H );
where int p
is the position of the element, and PriorityQueue
is defined as the following:
typedef struct HeapStruct *PriorityQueue;
struct HeapStruct {
ElementType *Elements;
int Capacity;
int Size;
};
Sample program of judge:
#include <stdio.h>
#include <stdlib.h>
typedef int ElementType;
#define MinData -1
typedef struct HeapStruct *PriorityQueue;
struct HeapStruct {
ElementType *Elements;
int Capacity;
int Size;
};
PriorityQueue Initialize( int MaxElements ); /* details omitted */
void PercolateUp( int p, PriorityQueue H );
void PercolateDown( int p, PriorityQueue H );
void Insert( ElementType X, PriorityQueue H )
{
int p = ++H->Size;
H->Elements[p] = X;
PercolateUp( p, H );
}
ElementType DeleteMin( PriorityQueue H )
{
ElementType MinElement;
MinElement = H->Elements[1];
H->Elements[1] = H->Elements[H->Size--];
PercolateDown( 1, H );
return MinElement;
}
int main()
{
int n, i, op, X;
PriorityQueue H;
scanf("%d", &n);
H = Initialize(n);
for ( i=0; i<n; i++ ) {
scanf("%d", &op);
switch( op ) {
case 1:
scanf("%d", &X);
Insert(X, H);
break;
case 0:
printf("%d ", DeleteMin(H));
break;
}
}
printf("\nInside H:");
for ( i=1; i<=H->Size; i++ )
printf(" %d", H->Elements[i]);
return 0;
}
/* Your function will be put here */
Sample Input:
9
1 10
1 5
1 2
0
1 9
1 1
1 4
0
0
Sample Output:
2 1 4 Inside H: 5 10 9
解答:
这题真的是好水啊……而且那个输入输出样例有必要给出么……直接说写最小堆的插入和删除操作就好了……都是常规操作啊
// // main.c // Percolate Up and Down // // Created by 余南龙 on 2016/10/31. // Copyright ? 2016年 余南龙. All rights reserved. // void PercolateUp( int p, PriorityQueue H ){ ElementType tmp = H->Elements[p]; while(p / 2 >= 1&&H->Elements[p / 2] > tmp){ H->Elements[p] = H->Elements[p / 2]; p = p / 2; } H->Elements[p] = tmp; } void PercolateDown( int p, PriorityQueue H ){ ElementType tmp = H->Elements[p]; while(1){ if(p * 2 + 1 <= H->Size){ if(H->Elements[p * 2 + 1] < H->Elements[p * 2]&&H->Elements[p * 2 + 1] < tmp){ H->Elements[p] = H->Elements[p * 2 + 1]; p = p * 2 + 1; } else if(H->Elements[p * 2 + 1] > H->Elements[p * 2]&&H->Elements[p * 2] < tmp){ H->Elements[p] = H->Elements[p * 2]; p = p * 2; } else{ break; } } else if(p * 2 <= H->Size){ if(H->Elements[p * 2] < tmp){ H->Elements[p] = H->Elements[p * 2]; p = p * 2; } else{ break; } } else{ break; } } H->Elements[p] = tmp; }
PTA Percolate Up and Down
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