poj2255Tree Recovery【二叉树重构】

来源：互联网发布：阿里云dns怎么样编辑：程序博客网时间：2024/05/17 23:18

大意：告诉你一棵二叉树的先序遍历和中序遍历求该二叉树的后续遍历

代码：

 1 #include <iostream> 2 #include <cstdio> 3 #include <cstring> 4 using namespace std; 5  6 const int maxn = 30; 7 char pr[maxn], mi[maxn]; 8  9 struct Node {10     int left;11     int right;12 }tr[maxn];13 14 int root;15 16 void init(int p) {17     tr[p].left = -1;18     tr[p].right = -1;19 }20 21 void fason(int pa, int son) {22     if(son < pa) {23         if(tr[pa].left == -1) {24             init(son);25             tr[pa].left = son;26         } else fason(tr[pa].left, son);27     } else {28         if(tr[pa].right == -1) {29             init(son);30             tr[pa].right = son;31         } else fason(tr[pa].right, son);32     }33 }34 35 void build_tree() {36     for(int i = 0; mi[i]; i++) {37         if(mi[i] == pr[0]) {38             root = i;39             init(root);40             break;41         }42     }43     for(int i =1; pr[i]; i++) {44         for(int j = 0; mi[j]; j++) {45             if(mi[j] == pr[i]) {46                 fason(root, j);47                 break;48             }49         }50     }51 }52 void pre_out(int p) {53     printf("%c", mi[p]);54     if(tr[p].left != -1) pre_out(tr[p].left);55     if(tr[p].right != -1) pre_out(tr[p].right);56 }57 void mid_out(int p) {58     if(tr[p].left != -1) mid_out(tr[p].left);59     printf("%c", mi[p]);60     if(tr[p].right != -1) mid_out(tr[p].right);61 }62 63 void back_out(int p) {64     if(tr[p].left != -1) back_out(tr[p].left);65     if(tr[p].right != -1) back_out(tr[p].right);66     printf("%c", mi[p]);67 }68 69 int main() {70     while(EOF != scanf("%s %s",pr, mi) ) {71         build_tree();72         pre_out(root);73         puts("");74         mid_out(root);75         puts("");76         back_out(root);77         puts("");78     }79     return 0;80 }

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