zoukankan      html  css  js  c++  java
  • 【POJ 1469】COURSES

    COURSES
    Time Limit: 1000MS   Memory Limit: 10000K
    Total Submissions: 19760   Accepted: 7784

    Description

    Consider a group of N students and P courses. Each student visits zero, one or more than one courses. Your task is to determine whether it is possible to form a committee of exactly P students that satisfies simultaneously the conditions: 

    • every student in the committee represents a different course (a student can represent a course if he/she visits that course) 
    • each course has a representative in the committee 

    Input

    Your program should read sets of data from the std input. The first line of the input contains the number of the data sets. Each data set is presented in the following format: 

    P N 
    Count1 Student1 1 Student1 2 ... Student1 Count1 
    Count2 Student2 1 Student2 2 ... Student2 Count2 
    ... 
    CountP StudentP 1 StudentP 2 ... StudentP CountP 

    The first line in each data set contains two positive integers separated by one blank: P (1 <= P <= 100) - the number of courses and N (1 <= N <= 300) - the number of students. The next P lines describe in sequence of the courses �from course 1 to course P, each line describing a course. The description of course i is a line that starts with an integer Count i (0 <= Count i <= N) representing the number of students visiting course i. Next, after a blank, you抣l find the Count i students, visiting the course, each two consecutive separated by one blank. Students are numbered with the positive integers from 1 to N. 
    There are no blank lines between consecutive sets of data. Input data are correct. 

    Output

    The result of the program is on the standard output. For each input data set the program prints on a single line "YES" if it is possible to form a committee and "NO" otherwise. There should not be any leading blanks at the start of the line.

    Sample Input

    2
    3 3
    3 1 2 3
    2 1 2
    1 1
    3 3
    2 1 3
    2 1 3
    1 1

    Sample Output

    YES
    NO

    Source

     
    明显的二分图。
    因为数据太小直接用矩阵存储图。
    #include <cstdio>
    #include <cstring>
    
    using namespace std;
    
    int p, n, left[305];
    bool g[105][305], v[305];
    
    bool dfs(int x)
    {
        for (int i = 1; i <= n; ++i)
            if (g[x][i] && v[i])
            {
                v[i] = false;
                if (left[i] == 0 || dfs(left[i]))
                {
                    left[i] = x;
                    return true;
                }
            }
        return false;
    }
    
    int main()
    {
        int Test;
        scanf("%d", &Test);
        while (Test--)
        {
            scanf("%d%d", &p, &n);
            memset(g, false, sizeof(g));
            for (int i = 1; i <= p; ++i)
            {
                int num, x;
                scanf("%d", &num);
                while (num--)
                {
                    scanf("%d", &x);
                    g[i][x] = true;
                }
            }
            int ans = 0;
            memset(left, 0, sizeof(left));
            for (int i = 1; i <= p; ++i)
            {
                memset(v, true, sizeof(v));
                if (dfs(i)) ans++;
            }
            printf("%s
    ", ans == p ? "YES" : "NO");
        }
        return 0;
    }
  • 相关阅读:
    【数据结构】算法 Invert Binary Tree 翻转二叉树
    雪碧图
    闭包
    正则那些事
    JS添加,删除表格中的行那些事
    三目运算
    10个不能重复的随机数要求为55-109的整数, 要将10个随机数打印出来,并且将10个随机数里面能够被5整除的数打印出来,最后将能够被5整除的数叠加的结果打印出来
    输出从小到大排序好的五个不重复的随机整数,范围[10-23)。努力的人全世界都为你让路!你的努力终将美好!
    随机取10个在55-80之间的数,按照从小到大排序输出,冒泡排序
    求10个随机数,随机数要求为25-99的整数.能够被3整除的数
  • 原文地址:https://www.cnblogs.com/albert7xie/p/4906695.html
Copyright © 2011-2022 走看看