TREES ON THE LEVEL

转自http://blog.csdn.net/metaphysis/article/details/7101708

// UVa Problem 122 - Trees on the level

// Verdict: Accepted
// Submission Date: 2011-12-25
// UVa Run Time: 0.008s
//
// 版权所有（C）2011，邱秋。metaphysis # yeah dot net
//
// [解题方法]
// 本题可以归结为数据结构问题。步骤是建立树结构，检查是否完整，若完整则按深度输出节点。


#include <iostream>
#include <sstream>
#include <cstring>


using namespace std;


#define TAG 0
#define MAXN 256


struct node
{
struct node *parent;
struct node *childLeft, *childRight;
int value;
};


bool noComplete, printWhitespace;
int cache[MAXN][MAXN];
int count[MAXN];


void checkComplete(node * current)
{
if (current->value == TAG)
noComplete = true;
if (current->childLeft != NULL)
checkComplete(current->childLeft);
if (current->childRight != NULL)
checkComplete(current->childRight);
}


// 遍历树，检查叶子节点保存的路径和是否为目标值。
void travelTree(node * current, int depth)
{
cache[depth][count[depth]++] = current->value;
if (current->childLeft != NULL)
travelTree(current->childLeft, depth + 1);
if (current->childRight != NULL)
travelTree(current->childRight, depth + 1);
}


void clearTree(node * current)
{
if (current->childLeft != NULL)
clearTree(current->childLeft);
if (current->childRight != NULL)
clearTree(current->childRight);
delete current;
}


int main(int argc, char const *argv[])
{
char c;
node *root = new node;
root->childLeft = NULL;
root->childRight = NULL;
root->value = TAG;


while (cin >> c)
{
if (c == ' ')
continue;
if (c == '(')
{
string pairs;
while (cin >> c, c != ')')
pairs += c;


if (pairs.length())
{
istringstream iss(pairs);
int number;
string positions;
iss >> number >> c >> positions;


node *current = root;
for (int i = 0; i < positions.length(); i++)
{
if (positions[i] == 'L')
{
if (current->childLeft == NULL)
{
node *temp = new node;
temp->value = TAG;
temp->childLeft = NULL;
temp->childRight = NULL;
current->childLeft = temp;
}


current = current->childLeft;
}
else
{
if (current->childRight == NULL)
{
node *temp = new node;
temp->value = TAG;
temp->childLeft = NULL;
temp->childRight = NULL;
current->childRight = temp;
}


current = current->childRight;
}
}


if (current->value > 0)
current->value = TAG;
else
current->value = number;
}
else
{
noComplete = false;
checkComplete(root);


if (noComplete)
cout << "not complete\n";
else
{
memset(count, 0, sizeof(count));
travelTree(root, 0);


printWhitespace = false;
for (int i = 0; i < MAXN; i++)
for (int j = 0; j < count[i]; j++)
{
if (printWhitespace)
cout << " ";
else
printWhitespace = true;
cout << cache[i][j];
}
cout << endl;
}


clearTree(root);


root = new node;
root->childLeft = NULL;
root->childRight = NULL;
root->value = TAG;
}


}
}


return 0;
}