这就是一道最小费用最大流问题 最大流就体现到每一个'm'都能找到一个'H',但是要在这个基础上面加一个费用,按照题意费用就是(横坐标之差的绝对值加上纵坐标之差的绝对值) 然后最小费用最大流模板就是再用最短路算法找最小费用路径.然后在找到这条路径上面的最大流..就这样一直找下去 代码: 1 //这是一个最小费用最大流问题 2 //最大费用最小流只要在添加边的时候换一下位置就好了 3 //求最大费用最大流只需要把费用换成相反数,用最小费用最大流求解即可 4 #include <cstdio> 5…

题意:有一个矩阵,某些格有人,某些格有房子,每个人可以上下左右移动,问给每个人进一个房子,所有人需要走的距离之和最小是多少. 貌似以前见过很多这样类似的题,都不会,现在知道是用KM算法做了 KM算法目前还没弄懂,先套模板做 Sample Input 2 2 .m H. 5 5 HH..m ..... ..... ..... mm..H 7 8 ...H.... ...H.... ...H.... mmmHmmmm ...H.... ...H.... ...H.... 0 0 Sample Out…

http://poj.org/problem?id=2195 题意:有一个地图里面有N个人和N个家,每走一格的花费是1,问让这N个人分别到这N个家的最小花费是多少. 思路:通过这个题目学了最小费用最大流.最小费用最大流是保证在流量最大的情况下,使得费用最小. 建图是把S->人->家->T这些边弄上形成一个网络,边的容量是1(因为一个人只能和一个家匹配),边的费用是曼哈顿距离,反向边的费用是-cost. 算法的思想大概是通过SPFA找增广路径,并且找的时候费用是可以松弛的.当找到这样一条增…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=1533 On a grid map there are n little men and n houses. In each unit time, every little man can move one unit step, either horizontally, or vertically, to an adjacent point. For each little man, you need…

Going Home Time Limit: 10000/5000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 3125    Accepted Submission(s): 1590 Problem Description On a grid map there are n little men and n houses. In each unit time, every…

Going Home Time Limit: 10000/5000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 7405    Accepted Submission(s): 3907 Problem Description On a grid map there are n little men and n houses. In each unit time, every l…

Coding Contest Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)Total Submission(s): 1751    Accepted Submission(s): 374 Problem Description A coding contest will be held in this university, in a huge playground. The…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=3667 思路:由于花费的计算方法是a*x*x,因此必须拆边,使得最小费用流模板可用,即变成a*x的形式.具体的拆边方法为:第i次取这条路时费用为(2*i-1)*a (i<=5),每条边的容量为1.如果这条边通过的流量为x,那正好sigma(2*i-1)(1<<i<<x)==x^2.然后就是跑最小费用最大流了. #include<iostream> #include<…

Tour Time Limit: 3000/1000 MS (Java/Others)    Memory Limit: 65535/65535 K (Java/Others)Total Submission(s): 2925    Accepted Submission(s): 1407 Problem Description In the kingdom of Henryy, there are N (2 <= N <= 200) cities, with M (M <= 30000…

Special Fish Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 2189    Accepted Submission(s): 826 Problem Description There is a kind of special fish in the East Lake where is closed to campus of…