【代码】
1 #include <cstdio> 2 #include <cstdlib> 3 #include <cstring> 4 #include <algorithm> 5 using namespace std; 6 7 const int maxn = 50005; 8 //Tkey为输入主键与辅键的结构体 9 //key表示主键，aux表示辅键，index表示是输入的第几个结点 10 struct Tkey { 11 int key, aux, index; 12 } keys[maxn]; 13 //Tnode是BST结点的结构体，key表示主键，aux表示辅键 14 //father表示父结点的编号，leftChild和rightChild表示左右儿子结点 15 struct Tnode { 16 int key, aux, father, leftChild, rightChild; 17 } node[maxn]; 18 int n; 19 20 //排序的比较函数 21 bool cmp(const Tkey &a, const Tkey &b) { 22 return a.key < b.key; 23 } 24 25 int main() { 26 //读入数据 27 int i; 28 scanf("%d", &n); 29 for (i = 1; i <= n; ++i) { 30 scanf("%d%d", &keys[i].key, &keys[i].aux); 31 keys[i].index = i; 32 } 33 34 //按key对结点排序 35 sort(keys + 1, keys + n + 1, cmp); 36 37 //按key从小到大将结点插入BST 38 //father表示当前插入结点的父节点，leftChild表示当前插入结点的左儿子节点 39 //rightMost表示每次插入前BST最右的结点 40 int p, father, leftChild, rightMost = 0; 41 for (i = 1; i <= n; ++i) { 42 //寻找插入结点的父亲与左儿子 43 leftChild = 0; father = rightMost; 44 while (father != 0 && node[father].aux > keys[i].aux) { 45 leftChild = father; 46 father = node[father].father; 47 } 48 //将结点插入BST 49 p = keys[i].index; 50 node[p].key = keys[i].key; 51 node[p].aux = keys[i].aux; 52 node[p].father = father; 53 node[p].leftChild = leftChild; 54 node[p].rightChild = 0; 55 if (father != 0) 56 node[father].rightChild = p; 57 if (leftChild != 0) 58 node[leftChild].father = p; 59 rightMost = keys[i].index; 60 } 61 62 //输出答案 63 printf("YES "); 64 for (i = 1; i <= n; ++i) 65 printf("%d %d %d ", node[i].father, node[i].leftChild, node[i].rightChild); 66 return 0; 67 }