zoukankan      html  css  js  c++  java
  • ZOJ 3204 Connect them

    Connect them

    Time Limit: 1 Second      Memory Limit: 32768 KB

    You have n computers numbered from 1 to n and you want to connect them to make a small local area network (LAN). All connections are two-way (that is connecting computers i and j is the same as connecting computers j and i). The cost of connecting computer i and computer j is cij. You cannot connect some pairs of computers due to some particular reasons. You want to connect them so that every computer connects to any other one directly or indirectly and you also want to pay as little as possible.

    Given n and each cij , find the cheapest way to connect computers.

    Input

    There are multiple test cases. The first line of input contains an integer T (T <= 100), indicating the number of test cases. Then T test cases follow.

    The first line of each test case contains an integer n (1 < n <= 100). Then n lines follow, each of which contains n integers separated by a space. The j-th integer of the i-th line in these n lines is cij, indicating the cost of connecting computers i and j (cij = 0 means that you cannot connect them). 0 <= cij <= 60000, cij = cjicii = 0, 1 <= ij <= n.

    Output

    For each test case, if you can connect the computers together, output the method in in the following fomat:

    i1 j1 i1 j1 ......

    where ik ik (k >= 1) are the identification numbers of the two computers to be connected. All the integers must be separated by a space and there must be no extra space at the end of the line. If there are multiple solutions, output the lexicographically smallest one (see hints for the definition of "lexicography small") If you cannot connect them, just output "-1" in the line.

    Sample Input

    2
    3
    0 2 3
    2 0 5
    3 5 0
    2
    0 0
    0 0
    
    

    Sample Output

    1 2 1 3
    -1
    

    Hints:
    A solution A is a line of p integers: a1a2, ...ap.
    Another solution B different from A is a line of q integers: b1b2, ...bq.
    A is lexicographically smaller than B if and only if:
    (1) there exists a positive integer r (r <= pr <= q) such that ai = bi for all 0 < i < r and ar < br 
    OR

    (2) p < q and ai = bi for all 0 < i <= p

    最小生成树:

    #include <iostream>
    #include <string.h>
    #include <stdlib.h>
    #include <algorithm>
    #include <math.h>
    #include <stdio.h>
    
    using namespace std;
    const int INF=1e5;
    struct Node
    {
        int x;int y;
        int value;
    }a[10005];
    int cmp(Node a,Node b)
    {
        if(a.value==b.value)
        {
            if(a.x==b.x)
            {
                return a.y<b.y;
            }
            return a.x<b.x;
        }
        else
            return a.value<b.value;
    }
    struct node
    {
        int x;
        int y;
    }ans[INF+5];
    int cmp2(node a,node b)
    {
        if(a.x==b.x)
            return a.y<b.y;
        else
            return a.x<b.x;
    }
    int n;
    int father[INF+5];
    int find(int x)
    {
        if(father[x]!=x)
            father[x]=find(father[x]);
        return father[x];
    }
    
    int main()
    {
        int t;
        scanf("%d",&t);
        while(t--)
        {
            scanf("%d",&n);
            int tot=0;
            for(int i=1;i<=n;i++)
            {
                for(int j=1;j<=n;j++)
                {
                    scanf("%d",&a[++tot].value);
                    a[tot].x=i;
                    a[tot].y=j;
                    if(a[tot].value==0)
                        a[tot].value=INF;
                }
            }
            sort(a+1,a+tot+1,cmp);
            for(int i=1;i<=n;i++)
                father[i]=i;
            int cot=0;
            for(int i=1;i<=tot;i++)
            {
                if(a[i].value==INF)
                    continue;
                int xx=find(a[i].x);
                int yy=find(a[i].y);
                if(xx!=yy)
                {
                    father[xx]=yy;
                    ans[++cot].x=a[i].x;
                    ans[cot].y=a[i].y;
                }
            }
            int root=find(1);
            bool res=true;
            for(int i=2;i<=n;i++)
            {
                find(i);
                if(father[i]!=root)
                    res=false;
            }
            if(!res)
                printf("-1
    ");
            else
            {
                sort(ans+1,ans+1+cot,cmp2);
                for(int i=1;i<=cot;i++)
                {
                    if(i==cot)
                        printf("%d %d
    ",ans[i].x,ans[i].y);
                    else
                        printf("%d %d ",ans[i].x,ans[i].y);
                }
            }
            
            
        }
        return 0;
    }



  • 相关阅读:
    封装好的PHP分页类,简单好用--在开源看到的,取回来自己用
    php网站判断用户是否是手机访问的方法
    三种php连接access数据库方法
    php防止SQL注入详解及防范
    mysql sql语句大全
    java util 中set,List 和Map的使用
    web开发——写一个简单的表格导出操作
    JSP登录页面使用Enter键登录【转】
    PL/SQL 将旧表的一些字段赋值给新的表中的字段的做法
    PL/SQL设置主键自增
  • 原文地址:https://www.cnblogs.com/dacc123/p/8228562.html
Copyright © 2011-2022 走看看