297 - Quadtrees

描述：这道题就是求像素相加问题，给出了两个四叉树的先序输出，构建完这两个四叉树再合并，然后计算像素结果就ok了，注意，像素开始值是1024，也就是说输出如果大于1024就程序错了，关键是能够合并两个四叉树

#include <iostream>
#include <cstdio>
#include <cstring>
using namespace std;
struct Tnode
{
char v;
struct Tnode *first,*second,*third,*fourth;
Tnode ()
{
v=0;
first=second=third=fourth=NULL;
}
};
int len;
Tnode *creat_two_tree(char *b)//创建四叉树
{
Tnode *tree=new Tnode;
if(len<strlen(b))
{
tree->v=b[len];
if(b[len]=='p')
{
len++;//注意len++有四个，不是一个
tree->first=creat_two_tree(b);
len++;
tree->second=creat_two_tree(b);
len++;
tree->third=creat_two_tree(b);
len++;
tree->fourth=creat_two_tree(b);
}
}
return tree;
}
Tnode *creat_new_tree(Tnode *b, Tnode *c)//合并四叉树
{
Tnode *tree=new Tnode;
if(b->v=='f'||c->v=='f')tree->v='f';
else if(b->v=='e'&&c->v=='e')tree->v='e';
else
{
tree->v='p';
if(b->v=='p'&&c->v=='p')
{
tree->first=creat_new_tree(b->first,c->first);
tree->second=creat_new_tree(b->second,c->second);
tree->third=creat_new_tree(b->third,c->third);
tree->fourth=creat_new_tree(b->fourth,c->fourth);
}
else if(b->v=='p'&&c->v=='e')
{
tree->first=b->first;
tree->second=b->second;
tree->third=b->third;
tree->fourth=b->fourth;
}
else
{
tree->first=c->first;
tree->second=c->second;
tree->third=c->third;
tree->fourth=c->fourth;
}
}
return tree;
}
void sum(Tnode *tree,int count)//计算像素值和
{
if(tree)
{
if(tree->v=='f')len+=count;
count/=4;
sum(tree->first,count);
sum(tree->second,count);
sum(tree->third,count);
sum(tree->fourth,count);
}
}
int main()
{
//freopen("a.txt","r",stdin);
int n;
char s1[10010],s2[10010];
scanf("%d",&n);
while(n--)
{
memset(s1,0,sizeof(s1));
memset(s2,0,sizeof(s2));
scanf("%s%s",s1,s2);
len=0;
Tnode *root1=creat_two_tree(s1);
len=0;
Tnode *root2=creat_two_tree(s2);
Tnode *root=creat_new_tree(root1,root2);
len=0;
sum(root,1024);
printf("There are %d black pixels.\n",len);
}
return 0;
}