已知二叉树的前序遍历和中序遍历求整颗二叉树

实现代码：

 1 #include<iostream>
 2 #include<cstdio>
 3 #include<algorithm>
 4 #include<vector>
 5 #include<map>
 6 #include<queue>
 7 #include<set>
 8 #include<cmath>
 9 #include<list>
10 #include<cstring>
11 #include<string>
12 #define ll long long
13 #define ull unsigned long long
14 #define inf 0x3f3f3f3f
15 #define inff 0x7fffffff
16 using namespace std;
17 const int N = 10000 + 10;
18 const int M = 200000 + 10;
19 const int mod = 1e9 + 7;
20 
21 int pre[N], in[N];
22 
23 typedef struct node* BinTree;
24 
25 struct node {
26     int date;
27     BinTree left;
28     BinTree right;
29 };
30 
31 BinTree Build(int pre[], int in[], int size) {
32 
33     if (size <= 0) return NULL;
34     int rem = 0;
35     for (int i = 0; i < size; i++) {
36         if (in[i] == pre[0]) {
37             rem = i;
38             break;
39         }
40     }
41     BinTree tree = (BinTree)malloc(sizeof(struct node));
42     tree->date = pre[0];
43     tree->left = Build(pre + 1, in, rem);
44     tree->right = Build(pre + rem + 1, in + rem + 1, size - rem - 1);
45 
46     return tree;
47 }
48 
49 void postorder(BinTree T) {
50 
51     if (T == NULL) return;
52     else {
53         postorder(T->left);
54         postorder(T->right);
55         cout << T->date << " ";
56     }
57 
58     return;
59 }
60 
61 int main() {
62 
63     int n;
64     cin >> n;
65     for (int i = 0; i < n; i++) {
66         cin >> pre[i];
67     }
68     for (int i = 0; i < n; i++) {
69         cin >> in[i];
70     }
71     BinTree T;
72     T = Build(pre, in, n);
73     postorder(T);
74 
75     return 0;
76 }

 

 
 
 
posted @ 2022-04-17 21:59  Keyzee  阅读(50)  评论(0)    收藏  举报