1115. Counting Nodes in a BST (30)

分析：简单题——将bst树构造出来，然后给每个节点打上高度。最后求出树的高度。然后count树高的节点数加上树高节点数-1就ok了

 1 #include <iostream>
 2 #include <cstdio>
 3 
 4 #define MAXN 1003
 5 using namespace std;
 6 typedef struct Node{
 7     int key,hight;
 8     int left,right;
 9 }Node;
10 
11 Node node[MAXN];
12 int solve_hight[MAXN];
13 int main()
14 {
15     int n,index1,index2,max,a,b;
16     scanf("%d",&n);
17 
18     scanf("%d",&node[0].key);
19     node[0].left=node[0].right=-1;
20     for(int i=1;i<n;i++){
21         scanf("%d",&node[i].key);
22         node[i].left=node[i].right=-1;
23         int j=0;
24         while(1){
25             if(node[i].key>node[j].key)
26                 if(node[j].right!=-1)
27                     j=node[j].right;
28                 else
29                     {
30                         node[j].right=i;
31                         break;
32                     }
33             else
34                 if(node[j].left!=-1)
35                     j=node[j].left;
36                 else
37                     {
38                         node[j].left=i;
39                         break;
40                     }
41             }
42         }
43         index1=index2=0;
44         solve_hight[index2++]=0;
45         node[0].hight=1;
46         while(index1!=index2){
47             if(node[index1].left!=-1){
48                 solve_hight[index2++]=node[index1].left;
49                 node[node[index1].left].hight=node[index1].hight+1;
50             }
51             if(node[index1].right!=-1){
52                 solve_hight[index2++]=node[index1].right;
53                 node[node[index1].right].hight=node[index1].hight+1;
54             }
55             index1++;
56         }
57 
58         a=b=max=0;
59         for(int i=0;i<n;i++){
60             if(node[i].left==-1&&node[i].right==-1&&node[i].hight>max)max=node[i].hight;
61         }
62         for(int i=0;i<n;i++){
63             if(max==node[i].hight)a++;
64             if(max-1==node[i].hight)b++;
65         }
66         printf("%d + %d = %d
",a,b,a+b);
67 
68     return 0;
69 }

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1099. Build A Binary Search Tree (30)

类似于上题的简单题，看来pat的题目是一年年变难，难度都被刷上去了。先构建树的框架，然后将所给序列中序遍历，最后层次遍历给出结果。每个人都要找到最适合自己，能最快写出的树的层次遍历的代码。

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <algorithm>
 4 #define MAXN 105
 5 using namespace std;
 6 
 7 typedef struct Node{
 8     int left,right;
 9     Node(){
10         left=right=-1;
11     }
12 }Node;
13 Node node[MAXN];
14 int keynum[MAXN],ans[MAXN],mid[MAXN],count_num;
15 void mid_travel(int index){
16     if(node[index].left!=-1)
17         mid_travel(node[index].left);
18 
19     mid[count_num++]=index;
20     if(node[index].right!=-1)
21         mid_travel(node[index].right);
22 
23 }
24 int main()
25 {
26     int n,index1,index2;
27     scanf("%d",&n);
28     for(int i=0;i<n;i++)
29         scanf("%d%d",&node[i].left,&node[i].right);
30     index1=index2=0;
31     ans[index2++]=0;
32 
33     while(index1!=index2){
34         if(node[ans[index1]].left!=-1)
35             ans[index2++]=node[ans[index1]].left;
36         if(node[ans[index1]].right!=-1)
37             ans[index2++]=node[ans[index1]].right;
38         index1++;
39     }
40     for(int i=0;i<n;i++){
41         scanf("%d",&keynum[i]);
42     }
43     //得到中序遍历序列
44     sort(keynum,keynum+n);
45     count_num=0;
46     mid_travel(0);
47     bool flag=false;
48     for(int i=0;i<n;i++){
49         for(int j=0;j<n;j++)
50             if(ans[i]==mid[j]){
51                 if(!flag){
52                     printf("%d",keynum[j]);
53                     flag=true;
54                 }else
55                     printf(" %d",keynum[j]);
56                 break;
57             }
58     }
59     return 0;
60 }

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我要坚持一年，一年后的成功才是我想要的。