Sicily 1034. Forest

题目地址：1034. Forest

思路：

     网上很多说用深搜，很任性.......发现广搜也挺好用的，实验课打的(⊙o⊙)…orz........囧。

     先找根结点，根据根结点广搜深度，广搜宽度，不过要开一个数组，同一层的累加宽度。别忘了要判断是否合法。

     具体代码如下：

#include <iostream>
#include <cstring>
#include <queue>
using namespace std;

bool path[101][101];
bool visited[101];
bool Root[101];

int main()
{
    int n, m;
    while (cin >> n >> m && n)
    {
        memset(path, false, sizeof(path));
        memset(visited, false, sizeof(visited));
        memset(Root, true, sizeof(Root));

        bool flag = n > m ? true : false;
        for (int i = 1; i <= m; i++)
        {
            int node1, node2;
            cin >> node1 >> node2;
            if (node1 == node2) flag = false;
            path[node1][node2] = true;
        }
        if (flag == false) {
            cout << "INVALID
";
            continue;
        }
        
        for (int i = 1; i <= n; i++)
            for (int j = 1; j <= n; j++)
                if (path[j][i])
                    Root[i] = false;
        int maxwidth = 0;
        for (int i = 1; i <= n; i++)
            if (Root[i]) {
                maxwidth++;
                visited[i] = true;
            }
        queue<int> store;
        int depth, maxdepth;
        maxdepth = depth = 0;
        int width[101] = {0};
        for (int i = 1; i <= n; i++)
        {
            if (Root[i])
            {
                store.push(i);
                depth = 0;
                while (!store.empty())
                {
                    int size = store.size();
                    width[depth] += size;
                    while (size--)
                    {
                        for (int j = 1; j <= n; j++)
                            if (path[store.front()][j])
                            {
                                if (!visited[j]) {
                                    store.push(j);
                                    visited[j] = true;
                                }
                                else
                                    flag = false;
                            }
                        store.pop();
                    }
                    if (!store.empty())
                        depth++;
                }
                maxdepth = depth > maxdepth ? depth : maxdepth;
            }
        }
        
        for (int i = 1; i <= n; i++)
            if (!visited[i]) {
                flag = false;
                break;
            }
        
        for (int i = 0; i <= maxdepth; i++)
            maxwidth = width[i] > maxwidth ? width[i] : maxwidth;
        
        flag == false ? cout << "INVALID" : cout << maxdepth << " " << maxwidth;
        cout << endl;
    }

    return 0;
}