hdu 3829 Cat VS Dog(最大独立集)

题目地址：点击打开链接

题意：有p个孩子参观动物园，动物园里面有n只猫和m只狗，每个孩子喜欢猫讨厌狗，或者喜欢狗讨厌猫。只有把一个

孩子不喜欢的动物移走，喜欢的动物留下，这个孩子才会高兴。 问最多能使多少个孩子高兴。

思路: 一开始想着把猫和狗做二分图。。但不知道如何去建图了，而且高兴的孩子数也求不出。

正解应该是把喜欢猫的和喜欢狗的分为两个集合作二分图，如果A喜欢B讨厌的或者A讨厌B喜欢的那么建立关系。然后

求一个最大独立集（最大独立集=顶点数-最大匹配数）

代码：

#include<iostream>#include<cstdio>#include<cstring>#include<vector>using namespace std;const int maxn = 505;int n, m, p, numCater, numDoger, match[maxn];bool vis[maxn];vector<int> g[maxn];struct node{    char like[15], dislike[15];}cater[maxn], doger[maxn];bool dfs(int x){    for(int i = 0; i < g[x].size(); i++)    {        int to = g[x][i];        if(!vis[to])        {            vis[to] = 1;            if(match[to] == -1 || dfs(match[to]))            {                match[to] = x;                return 1;            }        }    }    return 0;}int Hungary(){    int res = 0;    memset(match, -1, sizeof(match));    for(int i = 0; i < numCater; i++)    {        memset(vis, 0, sizeof(vis));        res += dfs(i);    }    return res;}int main(void){    while(cin >> n >> m >> p)    {        for(int i = 0; i <= p; i++)            g[i].clear();        numCater = numDoger = 0;        for(int i = 1; i <= p; i++)        {            char a[15], b[15];            scanf(" %s %s", a, b);            if(a[0] == 'C')            {                strcpy(cater[numCater].like, a);                strcpy(cater[numCater].dislike, b);                numCater++;            }            else            {                strcpy(doger[numDoger].like, a);                strcpy(doger[numDoger].dislike, b);                numDoger++;            }        }        for(int i = 0; i < numCater; i++)            for(int j = 0; j < numDoger; j++)                if(!strcmp(cater[i].like, doger[j].dislike) || ! strcmp(cater[i].dislike, doger[j].like))                    g[i].push_back(j);        printf("%d\n", p-Hungary());    }    return 0;}

Cat VS Dog

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 125536/65536 K (Java/Others)
Total Submission(s): 3765    Accepted Submission(s): 1349

Problem Description

The zoo have N cats and M dogs, today there are P children visiting the zoo, each child has a like-animal and a dislike-animal, if the child's like-animal is a cat, then his/hers dislike-animal must be a dog, and vice versa.
Now the zoo administrator is removing some animals, if one child's like-animal is not removed and his/hers dislike-animal is removed, he/she will be happy. So the administrator wants to know which animals he should remove to make maximum number of happy children.

 

Input

The input file contains multiple test cases, for each case, the first line contains three integers N <= 100, M <= 100 and P <= 500.
Next P lines, each line contains a child's like-animal and dislike-animal, C for cat and D for dog. (See sample for details)

 

Output

For each case, output a single integer: the maximum number of happy children.

 

Sample Input

1 1 2C1 D1D1 C11 2 4C1 D1C1 D1C1 D2D2 C1

 

Sample Output

13
Hint
Case 2: Remove D1 and D2, that makes child 1, 2, 3 happy.
 

 

Source

2011 Multi-University Training Contest 1 - Host by HNU