算法导论9.1-1

 1 #include<iostream>
 2 
 3 using namespace std;
 4 
 5 #define Left(i)    i*2+1
 6 #define Right(i) i*2+2
 7 
 8 int size = 10;
 9 
10 void Exchange(int &a, int &b)
11 {
12     int c = a;
13     a = b;
14     b = c;
15 }
16 
17 void MaxHeap(int a[], int i)
18 {
19     int l = Left(i);
20     int r = Right(i);
21     int largest = i;
22     if (l < size&&a[l] < a[largest])
23         largest = l;
24     if (r < size&&a[r] < a[largest])
25         largest = r;
26     if (largest != i)
27     {
28         Exchange(a[largest], a[i]);
29         MaxHeap(a, largest);
30     }
31 }
32 
33 void BuildHeap(int a[])
34 {
35     for (int i = (size - 1) / 2; i >= 0; i--)
36     {
37         MaxHeap(a, i);
38     }
39 }
40 
41 int main()
42 {
43     int a[] = { 16, 4, 10, 14, 14, 9, 3, 2, 8, 1 };
44     BuildHeap(a);
45     for (int i = 0; i < 10; i++)
46         cout << a[i] << "    ";
47     if (a[Left(0)] < a[Right(0)])
48         cout << endl << a[Left(0)] << endl;
49     else
50         cout << endl<< a[Right(0)] << endl;
51 }