UVa 1556 Disk Tree

方法： Trie

其实就是建树，node里存文件名。因为最后同目录下的文件要按照文件名顺序输出，所以储存child pointer的时候用了map，自带排序。下面的code是动态分配内存，然而用数组也可以，参见trie template。

Code:

#include <cstdio>
#include <cstring>
#include <algorithm>
#include <iostream>
#include <string>
#include <vector>
#include <stack>
#include <bitset>
#include <cstdlib>
#include <cmath>
#include <set>
#include <list>
#include <deque>
#include <map>
#include <queue>
#include <fstream>
#include <cassert>
#include <unordered_map>
#include <unordered_set>
#include <cmath>
#include <sstream>
#include <time.h>
#include <complex>
#include <iomanip>
#define Max(a,b) ((a)>(b)?(a):(b))
#define Min(a,b) ((a)<(b)?(a):(b))
#define FOR(a,b,c) for (ll (a)=(b);(a)<(c);++(a))
#define FORN(a,b,c) for (ll (a)=(b);(a)<=(c);++(a))
#define DFOR(a,b,c) for (ll (a)=(b);(a)>=(c);--(a))
#define FORSQ(a,b,c) for (ll (a)=(b);(a)*(a)<=(c);++(a))
#define FORC(a,b,c) for (char (a)=(b);(a)<=(c);++(a))
#define FOREACH(a,b) for (auto &(a) : (b))
#define rep(i,n) FOR(i,0,n)
#define repn(i,n) FORN(i,1,n)
#define drep(i,n) DFOR(i,n-1,0)
#define drepn(i,n) DFOR(i,n,1)
#define MAX(a,b) a = Max(a,b)
#define MIN(a,b) a = Min(a,b)
#define SQR(x) ((LL)(x) * (x))
#define Reset(a,b) memset(a,b,sizeof(a))
#define fi first
#define se second
#define mp make_pair
#define pb push_back
#define all(v) v.begin(),v.end()
#define ALLA(arr,sz) arr,arr+sz
#define SIZE(v) (int)v.size()
#define SORT(v) sort(all(v))
#define REVERSE(v) reverse(ALL(v))
#define SORTA(arr,sz) sort(ALLA(arr,sz))
#define REVERSEA(arr,sz) reverse(ALLA(arr,sz))
#define PERMUTE next_permutation
#define TC(t) while(t--)
#define forever for(;;)
#define PINF 1000000000000
#define newline '
'

#define test if(1)if(0)cerr
using namespace std;
using namespace std;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int,int> ii;
typedef pair<double,double> dd;
typedef pair<char,char> cc;
typedef vector<ii> vii;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll, ll> l4;
const double pi = acos(-1.0);


struct node
{
    map<string, node*> child;
};
stack<node*> inuse;
stack<node*> ready;
void clear()
{
    while (!inuse.empty())
    {
        ready.push(inuse.top());
        ready.top()->child.clear();
        inuse.pop();
    }
}
node* new_node()
{
    if (ready.empty())
    {
        node* temp = new node();
        ready.push(temp);
    }
    auto ret = ready.top();
    ready.pop();
    return ret;
}
int n;
node *root;
void add(const string &str)
{
    int last = 0;
    int len = str.length();
    node *cur = root;
    for (int i = 0; i <= len; ++i)
    {
        if (i == len || str[i] == '\')
        {
            string nxt = str.substr(last, i-last);
            last = i+1;
            if (cur->child.count(nxt) == 0)
            {
                cur->child[nxt] = new_node();
            }
            cur = cur->child[nxt];
        }
    }
}
void print(node* cur, int space)
{
    const string s = string(space, ' ');
    for (auto &pr : cur->child)
    {
        cout << s << pr.first << newline;
        print(pr.second, space+1);
    }
}
int main()
{
    while (cin >> n)
    {
        root = new_node();
        string line;
        rep(i, n)
        {
            cin >> line;
            add(line);
        }
        print(root, 0);
        clear();
        cout << newline;
    }
    
}
/*
 2
 3 2 cat dog mouse rat bat 1 1 abc cab
 */