HDU-1507 Uncle Tom's Inherited Land*

相邻空格连边，求最大匹配。

#include <cmath>
#include <cstdlib>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <fstream>
#include <iostream>

#define rep(i, l, r) for(int i=l; i<=r; i++)
#define clr(x, c) memset(x, c, sizeof(x))
#define N 109
#define MAX 1<<30
#define ll long long

using namespace std;
int read()
{
	int x=0, f=1; char ch=getchar();
	while (ch<'0' || ch>'9') { if (ch=='-') f=-1; ch=getchar(); }
	while (ch>='0' && ch<='9') { x=x*10+ch-'0'; ch=getchar(); }
	return x*f;
}

struct edge{int y1, y2, n;} e[N*N]; int fir[N][N], en;
int n, m, k1[N][N], k2[N][N], ans;
bool b[N][N], map[N][N];

void Add(int x1, int x2, int y1, int y2) 
{ 
	en++, e[en].y1=y1, e[en].y2=y2, e[en].n=fir[x1][x2], fir[x1][x2]=en; 
}

bool Find(int x1, int x2)
{
	int o=fir[x1][x2], y1=e[o].y1, y2=e[o].y2;
	while (o)
	{
		if (!b[y1][y2])
		{
			b[y1][y2]=1; if (!k1[y1][y2] || Find(k1[y1][y2], k2[y1][y2])) 
				{ k1[y1][y2]=x1; k2[y1][y2]=x2; return true; }
		}
		o=e[o].n, y1=e[o].y1, y2=e[o].y2;
	}
	return false;
}

int main()
{
	while (scanf("%d%d", &n, &m) && (n || m))
	{
		int x, y, q=read(); ans=en=0; clr(fir, 0); clr(k1, 0); clr(k2, 0); clr(map, 1);
		rep(i, 1, q) map[x=read()][y=read()]=0;
		rep(i, 1, n) rep(j, 1, m) if (map[i][j])
		{
			if (i-1>0 && map[i-1][j]) Add(i, j, i-1, j);
			if (j-1>0 && map[i][j-1]) Add(i, j, i, j-1);
			if (i+1<=n && map[i+1][j]) Add(i, j, i+1, j);
			if (j+1<=m && map[i][j+1]) Add(i, j, i, j+1);
		}
		rep(i, 1, n) rep(j, 1, m) if ((i+j)%2 && map[i][j])
		{
			clr(b, 0);
			if (Find(i, j)) ans++;
		}
		printf("%d
", ans);
		rep(i, 1, n) rep(j, 1, m) if ((i+j)%2==0 && k1[i][j])	
		{
			printf("(%d,%d)--(%d,%d)
", k1[i][j], k2[i][j], i, j);
		}
		printf("
");
	}
	return 0;
}