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#include <vector>
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#include <string>
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#include <stdlib.h>
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using namespace std;
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typedef int ElemType;
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typedef struct node
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{
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ElemType data; //数据元素
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struct node* lchild; //指向左孩子结点
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struct node* rchild; //指向右孩子结点
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} BTNode; //二叉链结点类型
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BTNode* CreateBTree(ElemType a[], ElemType b[], int n)
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//对应例2.8的算法由先序序列a[0..n-1]和中序序列b[0..n-1]建立二叉链
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{
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int k;
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if (n <= 0) return NULL;
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ElemType root = a[0]; //根结点值
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BTNode* bt = (BTNode*)malloc(sizeof(BTNode));
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bt->data = root;
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for (k = 0; k < n; k++) //在b中查找b[k]=root的根结点
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if (b[k] == root)
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break;
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bt->lchild = CreateBTree(a + 1, b, k); //递归创建左子树
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bt->rchild = CreateBTree(a + k + 1, b + k + 1, n - k - 1); //递归创建右子树
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return bt;
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}
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void DispBTree(BTNode* bt)
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//采用括号表示输出二叉链bt
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{
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if (bt != NULL)
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{
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printf("%d", bt->data);
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if (bt->lchild != NULL || bt->rchild != NULL)
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{
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printf("("); //有孩子结点时才输出(
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DispBTree(bt->lchild); //递归处理左子树
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if (bt->rchild != NULL) printf(","); //有右孩子结点时才输出,
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DispBTree(bt->rchild); //递归处理右子树
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printf(")"); //有孩子结点时才输出)
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}
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}
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}
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void DestroyBTree(BTNode*& bt)
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//释放以bt为根结点的二叉树
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{
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if (bt != NULL)
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{
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DestroyBTree(bt->lchild);
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DestroyBTree(bt->rchild);
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free(bt);
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}
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}
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int maxsum = 0; //全局变量:存放最大路径和。
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vector<int> maxpath; //全局变量:存放最大路径
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void Findmaxpath(BTNode* bt, vector <int > apath, int asum)
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//求根结点到叶结点的路径和最大的路径
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{
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if (bt == NULL) //空树直接返回
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return;
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apath.push_back(bt->data);
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asum += bt->data; //bt结点加入apath
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if (bt->lchild == NULL && bt->rchild == NULL) //bt结点为叶结点
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{
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if (asum - maxsum)
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{
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maxsum = asum;
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maxpath.clear();
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maxpath = apath;
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}
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}
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Findmaxpath(bt->lchild, apath, asum); //在左子树中查找
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Findmaxpath(bt->rchild, apath, asum); //在右子树中查找
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}
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int main()
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{
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BTNode* bt;
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ElemType a[] = { 5,2,3,4,1,6 };
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ElemType b[] = { 2,3,5,1,4,6 };
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int n = sizeof(a)/sizeof(a[0]);
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bt = CreateBTree(a,b,n);
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printf("实验结果:\n");
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printf("二叉树bt:");
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DispBTree(bt);
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printf("'in");
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printf("最大路径");
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vector<int> apath;
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int asum = 0;
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Findmaxpath(bt,apath,asum);
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printf("路径和: % d，路径 : ",maxsum);
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for (int i=0;i < maxpath.size();i++)
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printf("%d ",maxpath[i]);
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printf("\n");
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printf("销毁树bt\n");
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DestroyBTree(bt);
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}
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