杭电 hdu 1507 Uncle Tom's Inherited Land*（二分图，最大匹配）

/* THE PROGRAM IS MADE BY PYY *//*----------------------------------------------------------------------------//Copyright (c) 2011 panyanyany All rights reserved.URL   : http://acm.hdu.edu.cn/showproblem.php?pid=1507Name  : 1507 Uncle Tom's Inherited Land*Date  : Friday，August 27, 2011Time Stage : 3 hoursResult:45045242011-08-27 21:30:42Accepted150731MS420K2051 BC++pyyTest Data:Review:一开始犯了个很白痴的错误，结果做了几个小时……若将棋盘中相邻的格子分别用黑白染色的话，则同一种颜色的格子必然会出现：(x+y) 为奇数的情况，所以通过(x+y)&1是否为可以判断是否同一种颜色//----------------------------------------------------------------------------*/#include <stdio.h>#include <string.h>#include <stdlib.h>#define max(a, b) (((a) > (b)) ? (a) : (b))#define min(a, b) (((a) < (b)) ? (a) : (b))#define FALSE0#define TRUE1#define infinity    0x0f0f0f0f#define minus_inf    0x80808080#define MAXSIZE109#define SafeAccess(x, y) ((0 < (x) && (x) <= n) && (0 < (y) && (y) <= m))int n, m, k ;int map[MAXSIZE][MAXSIZE], cover[MAXSIZE][MAXSIZE] ;int dir[4][2] = {{0, 1}, {0, -1}, {1, 0}, {-1, 0}} ;typedef struct tagNODE {int x, y ;} NODE ;NODE link[MAXSIZE][MAXSIZE] ;int find (int x, int y){int i, j, k ;for (k = 0 ; k < 4 ; ++k){i = x + dir[k][0] ;j = y + dir[k][1] ;if (SafeAccess (i, j) && !map[i][j] && cover[i][j] == FALSE){cover[i][j] = TRUE ;if (link[i][j].x == 0 || find (link[i][j].x, link[i][j].y)){link[i][j].x = x ;link[i][j].y = y ;return 1 ;}}}return 0 ;}int main (){int i, j, x, y, sum ;while (scanf ("%d%d", &n, &m), n | m){memset (map, 0, sizeof (map)) ;scanf ("%d", &k) ;for (i = 1 ; i <= k ; ++i){scanf ("%d%d", &x, &y) ;map[x][y] = 1 ;}sum = 0 ;memset (link, FALSE, sizeof (link)) ;// 从白色格子开始找for (i = 1 ; i <= n ; ++i)for (j = 1 ; j <= m ; ++j)if (!map[i][j] && (i+j)&1){memset (cover, FALSE, sizeof (cover)) ;// 找黑色格子的匹配项sum += find (i, j) ;}printf ("%d\n", sum) ;for (i = 1 ; i <= n ; ++i)for (j = 1 ; j <= m ; ++j)if (link[i][j].x){printf ("(%d,%d)--(%d,%d)\n", i, j, link[i][j].x, link[i][j].y) ;}}return 0 ;}