POJ 3020 Antenna Placement

解题思路:求解最大独立集，转而求解最小顶点覆盖->最大流问题

#include <iostream>
using namespace std;

int t;
int father[405];
bool visit[405];
struct
{
    int x,y;
}point[405];

int Search(int x)
{
    for (int i = 1; i < t; i++)
    {
        if (!visit[i] && (abspoint[x].x - point[i].x) + abs(point[x].y - point[i].y)) == 1)
        {
            visit[i] = true;
            if (father[i] == 0 || Search(father[i]))
            {
                father[i] = x;
                return 1;
            }
        }
    }
    return 0;
}

int main()
{
    int k, n, m, u, v, s, row, col;
    char ch;
    const int dir[4][2] = {{-1, 0}, {1, 0}, {0, -1}, {0, 1}};
    cin >> k;
    while (k--)
    {
        memset(father, 0, sizeof(father));
        t = 1; s = 0;
        cin >> n >> m;
        for (int i = 0; i < n; i++)
            for (int j = 0; j < m; j++)
            {
                cin >> ch;
                if (ch == '*')
                {
                    point[t].y = i;
                    point[t++].x = j;
                }
            }
        for (int i = 1; i < t; i++)
        {
            memset(visit, 0, sizeof(visit));
            s += Search(i);
        }
        t = t - s / 2 - 1;
        cout << t << endl;;
    }
    return 0;
}