03-树2 List Leaves (25 分)

发布时间：2020-12-14 00:57:00 所属栏目：Linux 来源：网络整理

导读：Given a tree,you are supposed to list all the leaves in the order of top down,and left to right. Input Specification: Each input file contains one test case. For each case,the first line gives a positive integer? N?( ≤) which is the total

Given a tree,you are supposed to list all the leaves in the order of top down,and left to right.

Input Specification:

Each input file contains one test case. For each case,the first line gives a positive integer?

Output Specification:

For each test case,print in one line all the leaves‘ indices in the order of top down,and left to right. There must be exactly one space between any adjacent numbers,and no extra space at the end of the line.

Sample Input:

8
1 -
- -
0 -
2 7
- -
- -
5 -
4 6

Sample Output:

4 1 5

  1 #include <cstdio> 
  2 #include <stdlib.h>
  3 const int maxn = 12;
  4 struct TreeNode {
  5     int lchild,rchild;
  6 } tree[maxn];
  7 
  8 typedef int ElementType;
  9 typedef int Position;
 10 struct QNode {
 11     ElementType *Data;     /* 存储元素的数组 */
 12     Position Front,Rear;  /* 队列的头、尾指针 */
 13     int MaxSize;           /* 队列最大容量 */
 14 };
 15 
 16 typedef struct QNode *Queue;
 17  
 18 Queue CreateQueue( int MaxSize )
 19 {
 20     Queue Q = (Queue)malloc(sizeof(struct QNode));
 21     Q->Data = (ElementType *)malloc(MaxSize * sizeof(ElementType));
 22     Q->Front = Q->Rear = 0;
 23     Q->MaxSize = MaxSize;
 24     return Q;
 25 }
 26  
 27 bool IsFull( Queue Q )
 28 {
 29     return ((Q->Rear+1)%Q->MaxSize == Q->Front);
 30 }
 31  
 32 bool AddQ( Queue Q,ElementType X )
 33 {
 34     if ( IsFull(Q) ) {
 35         printf("队列满");
 36         return false;
 37     }
 38     else {
 39         Q->Rear = (Q->Rear+1)%Q->MaxSize;
 40         Q->Data[Q->Rear] = X;
 41         return true;
 42     }
 43 }
 44  
 45 bool IsEmpty( Queue Q )
 46 {
 47     return (Q->Front == Q->Rear);
 48 }
 49  
 50 ElementType DeleteQ( Queue Q )
 51 {
 52     if ( IsEmpty(Q) ) { 
 53         printf("队列空");
 54         return -1;
 55     }
 56     else  {
 57         Q->Front =(Q->Front+1)%Q->MaxSize;
 58         return  Q->Data[Q->Front];
 59     }
 60 }
 61 
 62 int buildTree() {
 63     int n;
 64     scanf("%d",&n);
 65 
 66     for(int i=0; i<n; i++) {
 67         getchar();
 68         char tl,tr;
 69         scanf("%c %c",&tl,&tr);
 70         if(tl == ‘-‘) tree[i].lchild = -1;
 71         else tree[i].lchild = tl - ‘0‘;
 72         if(tr == ‘-‘) tree[i].rchild = -1;
 73         else tree[i].rchild = tr - ‘0‘;
 74     }
 75     return n;
 76 }
 77 int num = 0;
 78 void traversal(int root) {
 79     if(root != -1) {
 80         num++;
 81         traversal(tree[root].lchild);
 82         traversal(tree[root].rchild);
 83     }
 84 }
 85 int findroot(int maxsize) {
 86     
 87     for(int i=0; i<maxsize; i++) {
 88         num = 0;
 89         traversal(i);
 90         if(num == maxsize) {
 91             return i;
 92         }
 93     }
 94     
 95 }
 96 
 97 int flag = 1;
 98 void lOTrav(int root) {
 99     Queue Q;
100     int temp;
101     
102     if(root == -1) return;
103     
104     Q = CreateQueue(12);
105     AddQ(Q,root);
106     while(!IsEmpty(Q)) {
107         temp = DeleteQ( Q );
108         if(tree[temp].lchild == -1 && tree[temp].rchild == -1) {
109             if(flag) {
110                 printf("%d",temp);
111                 flag = 0;
112             }
113             else printf(" %d",temp);
114         }
115         if(tree[temp].lchild != -1) AddQ( Q,tree[temp].lchild );
116         if(tree[temp].rchild != -1) AddQ( Q,tree[temp].rchild );
117         
118         
119     }
120     
121 } 
122 
123 
124 int main() {
125     int maxsize = buildTree();
126     int roota = findroot(maxsize);
127     lOTrav(roota);
128     
129     
130     
131     return 0;
132 }

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（编辑：李大同）

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