noip2004 FBI树

全为0的串为B串,全为1的串为I串，其余称为F串。

#include<string.h>
#include<cstdio>
#include<cstdlib>
#include<vector>
#include<iostream>
using namespace std;

const int NMAX=(1<<11)+1;

struct node
{
	char c;
	int value;
	int leftson,rightson;
};

int N,i,j;

node tree[NMAX];

char check(int left,int right)
{
	if(tree[left].c=='B'&&tree[right].c=='B')
	return 'B';
	else if(tree[left].c=='I'&&tree[right].c=='I')
	return 'I';
	else 
	return 'F';
}

void LRD(int root)
{
	if(root!=-1)
	{
		LRD(tree[root].leftson);
		LRD(tree[root].rightson);
		printf("%c",tree[root].c);
	}
}

int main()
{
	scanf("%d",&N);
	for(i=(1<<N);i<(1<<(N+1));i++)
	{
		scanf("%d",&tree[i].value);
		tree[i].leftson=-1;
		tree[i].rightson=-1;
		if(tree[i].value)
		tree[i].c='I';
		else 
		tree[i].c='B';
	}
	int temp=N-1;
	while(temp>=0)
	{
		for(i=1<<temp;i< 1<<(temp+1);i++)
		{
			tree[i].leftson=2*i;
			tree[i].rightson=2*i+1;
			tree[i].c=check(2*i,2*i+1);
		}
		temp--;
	}
	LRD(1);
	printf("\n");
	return 0;
}