列出叶结点

 1 #include <iostream>
 2 #include <queue>
 3 #include <vector>
 4 #include <cstring>
 5 #define MAXSIZE 10
 6 using namespace std;
 7 
 8 struct TreeNode {
 9     char data;
10     int cl;
11     int cr;
12 } t[MAXSIZE];
13 queue<int> q;
14 vector<int> v;
15 int CreateTree(struct TreeNode t[]) {
16     int N, root;
17     cin >> N;
18     if(!N) return -1;
19     int check[N];//用来标记该结点是否有父节点
20     memset(check, 0, sizeof(check));
21     for(int i=0; i<N; ++i) {
22         t[i].data=i+‘0‘;
23         char tcl, tcr;
24         cin >> tcl >> tcr;
25         if(tcl!=‘-‘) {
26             t[i].cl = tcl-‘0‘;
27             check[t[i].cl] = 1;
28         }
29         else t[i].cl = -1;
30         if(tcr!=‘-‘) {
31             t[i].cr = tcr-‘0‘;
32             check[t[i].cr] = 1;
33         }
34         else t[i].cr = -1;
35     }
36     int index;
37     for(index=0; index<N; index++) {
38         if(!check[index]) break;//没有父结点则为根结点
39     }
40     root = index;
41     return root;
42 }
43 void bfs(){
44     for(int i=0;i<q.size();i++){
45         int temp=q.front();
46         q.pop();
47         if(t[temp].cl==-1 && t[temp].cr==-1)
48             v.push_back(temp);
49         if(t[temp].cl!=-1)
50             q.push(t[temp].cl);
51         if(t[temp].cr!=-1)
52             q.push(t[temp].cr);    
53     }
54     if(q.size()) bfs();
55 }
56 int main(){
57     int r=CreateTree(t);
58     q.push(r);
59     bfs();
60     for(auto it=v.begin();it!=v.end();it++){
61         if(it!=v.begin())
62             cout << " ";
63         cout << *it;
64     }
65     cout << endl;
66 }