堆

 1 int heap[maxn], n;
 2 void heapPop() {
 3     swap(heap[1], heap[n]);
 4     -- n;
 5     for (int i = 1, j; i <= n; i = j) {
 6         if (i * 2 + 1 > n || heap[i * 2] < heap[i * 2 + 1]) {
 7             j = i * 2;
 8         } else {
 9             j = i * 2 + 1;
10         }
11         if (heap[i] > heap[j]) {
12             swap(heap[i], heap[j]);
13         } else {
14             break;
15         }
16     }
17 }
18 void heapInsert(int x) {
19     heap[++ n] = x;
20     for (int i = n, j; i > 1; i = j) {
21         j = i / 2;
22         if (heap[i] < heap[j]) {
23             swap(heap[i], heap[j]);
24         } else {
25             break;
26         }
27     }
28 }
29 /*
30                      1
31                     / 
32                     2  3
33                    /  / 
34                    4 5 6 7
35 二分之一n(整除)一定是父节点 
36 n的儿子是2n+1,2n+2（以0为根） 
37 */