构造次优查找树
#include <iostream> #include <math.h> using namespace std; typedef struct BiTNode { int data; int LTag,RTag; //标志位，=1表示lchild或rchild指示结点的左右孩子，=0表示指示结点的前驱后继 struct BiTNode *lchild,*rchild; }BiTNode, *BiTree; typedef BiTree SOSTree; //次优查找树用二茬链表存储结构 typedef struct SSTable{ double weight[20]; int elem[20]; int length; }SSTable; void SecondOptimal(BiTree &T, int R[], double sw[], int low, int high); void CreateSOSTree(SOSTree &T, SSTable ST); void FindSW(double sw[], SSTable ST); void SecondOptimal(BiTree &T, int R[], double sw[], int low, int high) { //由有序表R[low..high]，以及其累计权值表sw(sw[0]=0)递归构造次优查找树T int i,j; i = low; double min = fabs(sw[high]-sw[low]); double dw = sw[high] + sw[low-1]; for(j=low+1; j<=high; ++j) if(fabs(dw-sw[j]-sw[j-1]) < min) { i=j; min = fabs(dw-sw[j]-sw[j-1]); }; T = (BiTree)malloc(sizeof(BiTNode)); T->data = R[i]; //生成结点 cout<<T->data<<endl; T->lchild = NULL; T->rchild = NULL; if(i == low) T->lchild = NULL; //左子树空 else SecondOptimal(T->lchild, R, sw, low, i-1); //构造左子树 if(i == high) T->rchild = NULL; //右子树空 else SecondOptimal(T->rchild, R, sw, i+1, high); //构造右子树 } void CreateSOSTree(SOSTree &T, SSTable ST) { //由有序表ST，构造一棵次优查找树T，ST的数据元素含义权域weight double sw[20]; if(ST.length == 0) T = NULL; else { FindSW(sw, ST); //按有序表ST计算各数据元素的weight域累计权值表sw SecondOptimal(T, ST.elem, sw, 1, ST.length); } } void FindSW(double sw[], SSTable ST) { //按有序表ST计算各数据元素的weight域累计权值表sw int i,j; sw[0] = 0; for(i=1; i<=ST.length; ++i) sw[i] = sw[0] + ST.elem[i]; } void PreOrderTraverse(BiTree T) { if(T){ /*以先序方式遍历,若要以中序或后序遍历，只需改变以下三句顺序*/ cout<<T->data<<endl; PreOrderTraverse(T->lchild); PreOrderTraverse(T->rchild); } } int main() { SSTable ST; double a[10] = {0,1,1,2,5,3,4,4,3,5}; int i; for(i=0; i<10; ++i) { ST.elem[i] = i; ST.weight[i] = a[i]; } ST.length = 9; SOSTree T; CreateSOSTree(T, ST); cout<<"先根遍历："<<endl; PreOrderTraverse(T); return 0; }