uva 1556 - Disk Tree(字典树)

题目连接：uva 1556 - Disk Tree

题目大意：给出N个目录关系，然后按照字典序输出整个文件目录。

解题思路：以每个目录名作为字符建立一个字典树即可，每个节点的关系可以用map优化。

#include <cstdio>
#include <cstring>
#include <map>
#include <string>
#include <iostream>
#include <algorithm>

using namespace std;
const int maxn = 50005;
typedef map<string, int>::iterator iter;

struct Tire {
    int sz;
    map<string, int> g[maxn];

    void init();
    void insert(string s);
    void put(int u, int d);
}tree;

int main () {
    int n;
    string s;
    while (cin >> n && n) {
        tree.init();
        for (int i = 0; i < n; i++) {
            cin >> s;
            s += '\\';
            tree.insert(s);
        }
        tree.put(0, 0);
        cout << endl;
    }
    return 0;
}

void Tire::init() {
    sz = 1;
    g[0].clear();
}

void Tire::insert(string s) {

    int u = 0;
    string word = "";

    for (int i = 0; i < s.length(); i++) {
        if (s[i] == '\\') {

            if (!g[u].count(word)) {
                g[sz].clear();
                g[u][word] = sz++;
            }

            u = g[u][word];
            word = "";
        } else
            word += s[i];
    }
}

void Tire::put (int u, int d) {

    for (iter i = g[u].begin(); i != g[u].end(); i++) {
        for (int j = 0; j < d; j++)
            cout << " ";
        cout << i->first << endl;
        put(i->second, d + 1);
    }
}