四分树- UVa 297

Posted 2021-03-04 popodynasty

 1 #include <iostream>
 2 #define black ‘f‘
 3 #define white ‘e‘
 4 #define grey ‘p‘
 5 using namespace std;
 6 struct node{
 7     char type;
 8     node* upper_r;
 9     node* upper_l;
10     node* lower_l;
11     node* lower_r;
12 };
13 node* build_tree(){
14     node* root = new node;
15     cin >> root->type;
16     root->upper_l = root->upper_r = root->lower_l = root->lower_r = NULL;
17     if(root->type == grey){
18         root->upper_r = build_tree();
19         root->upper_l = build_tree();
20         root->lower_l = build_tree();
21         root->lower_r = build_tree();
22     }
23     return root;
24 }
25 int fun(node* a,node* b,int p){ // p 为边长 , 表示当前处理的子方格边长
26     if(a->type == black || b->type == black){ // 有黑
27         return p * p;
28     }else if(a->type == white && b->type == white){ // 全白
29         return 0;
30     }else if(a->type == white){ // 白灰
31         return fun(b,b,p);
32     }else if(b->type == white){ // 灰白
33         return fun(a,a,p);
34     }else{ // 灰灰
35         int sum = 0;
36         sum += fun(a->upper_r,b->upper_r,p>>1);
37         sum += fun(a->upper_l,b->upper_l,p>>1);
38         sum += fun(a->lower_l,b->lower_l,p>>1);
39         sum += fun(a->lower_r,b->lower_r,p>>1);
40         return sum;
41     }
42 }
43 int main(){
44     int t;
45     cin >> t;
46     while(t--){
47         cin.get();
48         node* a = build_tree();
49         cin.get();
50         node* b = build_tree();
51         int ans = fun(a,b,32);
52         cout << "There are " << ans <<" black pixels." << endl;
53     }
54     return 0;
55 }

题目不难，考查递归的基本应用和细节。

另外，本题使用宏定义能够让代码逻辑更加清晰。