백준 1991번 트리 순회 C++

출처 : https://www.acmicpc.net/problem/1991

 

노드와 트리를 직접 만들어서 풀다가 좀 오래걸렸는데 다른사람들 푼 것을 보니까 map으로 쉽게 풀 수 있었다.

 

#include <iostream>
#include <string>
#include <vector>
#include <math.h>
#include <algorithm>
#include <utility>
#include <stack>
#include <queue>
#include <math.h>
#include <set>
#include <map>
#include <list>
#include <unordered_map>
#include <unordered_set>
#include <iomanip>
#include <limits.h>

using namespace std;
using int64 = long long;

struct Node {
	Node* parent = nullptr;
	Node* left = nullptr;
	Node* right = nullptr;
	char value;
};

Node* root = nullptr;

Node* FindNode(Node* curr, char value) {
	if (curr->value == value)
		return curr;

	Node* left = nullptr;
	Node* right = nullptr;

	if (curr->left)
		left = FindNode(curr->left, value);
	if (curr->right)
		right = FindNode(curr->right, value);

	if (left != nullptr)
		return left;
	return right;
}

void Insert(char parent, char left, char right) {
	Node* currNode;
	if (root == nullptr) {
		currNode = new Node();
		currNode->value = parent;
		root = currNode;
	}
	else {
		currNode = FindNode(root, parent);
	}

	if (left != '.') {
		Node* leftNode = new Node();
		currNode->left = leftNode;

		leftNode->value = left;
		leftNode->parent = currNode;
	}
	if (right != '.') {
		Node* rightNode = new Node();
		currNode->right = rightNode;

		rightNode->value = right;
		rightNode->parent = currNode;
	}
}

void Print(Node* node, int traversalType) {
	if (node == nullptr)
		return;

	if (traversalType == 0)
		cout << node->value;

	Print(node->left, traversalType);

	if (traversalType == 1)
		cout << node->value;

	Print(node->right, traversalType);

	if (traversalType == 2)
		cout << node->value;
}

int main() {
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);

	int n;
	cin >> n;
	for (int i = 0; i < n; i++) {
		char a, b, c;
		cin >> a >> b >> c;
		Insert(a, b, c);
	}
	Print(root, 0);
	cout << "\n";
	Print(root, 1);
	cout << "\n";
	Print(root, 2);
};