构建最小堆
#include升序using namespace std; const int N = 1e5 + 10; int arr[N]; void adjust(int a[], int n, int i){ int mi = i, l = i * 2 + 1, r = i * 2 + 2; if(l < n && a[mi] > a[l]) mi = l; if(r < n && a[mi] > a[r]) mi = r; if(mi != i){ swap(a[mi], a[i]); adjust(a, n, mi); } } void buildMinHeap(int a[], int n){ for(int i = n / 2 - 1; i >= 0; i--){ adjust(a, n, i); } for(int i = n - 1; i >= 0; i--){ swap(a[0], a[i]); adjust(a, i, 0); } } int main(){ int n; cin >> n; for(int i = 0; i < n; i++) cin >> arr[i]; buildMinHeap(arr, n); return 0; }
构建最大堆
#includeusing namespace std; const int N = 1e5 + 10; int arr[N]; void adjust(int a[], int n, int i){ int ma = i, l = i * 2 + 1, r = i * 2 + 2; if(l < n && a[ma] < a[l]) ma = l; if(r < n && a[ma] < a[r]) ma = r; if(ma != i){ swap(a[ma], a[i]); adjust(a, n, ma); } } void buildMinHeap(int a[], int n){ for(int i = n / 2 - 1; i >= 0; i--){ adjust(a, n, i); } for(int i = n - 1; i >= 0; i--){ swap(a[0], a[i]); adjust(a, i, 0); } } int main(){ int n; cin >> n; for(int i = 0; i < n; i++) cin >> arr[i]; buildMinHeap(arr, n); return 0; }