Initial commit

Practical-Teaching/Data-Sructure/Big/2/2.3.cpp

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+#include <iostream>
+#include <queue>
+#include <vector>
+
+using namespace std;
+
+struct Node {
+	int weight;
+	string code;
+	Node *left, *right;
+	Node(int w) : weight(w), left(NULL), right(NULL) {}
+};
+
+struct cmp {
+	bool operator()(Node *a, Node *b) {
+		return a->weight > b->weight;
+	}
+};
+
+void generateHuffmanCode(Node *root, string str) {
+	if (!root)
+		return;
+	if (!root->left && !root->right) {
+		root->code = str;
+	}
+	generateHuffmanCode(root->left, str + "0");
+	generateHuffmanCode(root->right, str + "1");
+}
+
+int main() {
+	int n;
+	cin >> n;
+	priority_queue<Node *, vector<Node *>, cmp> pq;
+	for (int i = 0; i < n; ++i) {
+		int w;
+		cin >> w;
+		pq.push(new Node(w));
+	}
+	while (pq.size() != 1) {
+		Node *left = pq.top();
+		pq.pop();
+		Node *right = pq.top();
+		pq.pop();
+		Node *parent = new Node(left->weight + right->weight);
+		parent->left = left;
+		parent->right = right;
+		pq.push(parent);
+	}
+	generateHuffmanCode(pq.top(), "");
+	vector<Node *> nodes;
+	nodes.push_back(pq.top());
+	while (!nodes.empty()) {
+		Node *node = nodes.back();
+		nodes.pop_back();
+		if (node->left)
+			nodes.push_back(node->left);
+		if (node->right)
+			nodes.push_back(node->right);
+		if (!node->left && !node->right) {
+			cout << node->code << " ";
+		}
+	}
+	return 0;
+}