畅通工程

阳光穿透心脏的1/2处 2022-07-12 13:41 172阅读 0赞

<table style="font-family:&quot;Times New Roman&quot;; word-wrap:break-word"> 
 <tbody> 
  <tr> 
   <td align="center"> <h1 style="color:rgb(26,92,200)">畅通工程</h1> <strong><span style="font-family:Arial; color:green">Time Limit: 4000/2000 MS (Java/Others)&nbsp;&nbsp;&nbsp;&nbsp;Memory Limit: 65536/32768 K (Java/Others)<br> Total Submission(s): 50426&nbsp;&nbsp;&nbsp;&nbsp;Accepted Submission(s): 26894<br> </span></strong><br> <br> 
    <div style="height:38px; padding:0px 14px; color:rgb(124,169,237); font-size:18px; font-family:Arial; font-weight:bold">
      Problem Description 
    </div> 
    <div style="height:auto; margin:0px; padding:0px 20px; font-size:14px; font-family:&quot;Times New Roman&quot;; text-align:left">
      某省调查城镇交通状况，得到现有城镇道路统计表，表中列出了每条道路直接连通的城镇。省政府“畅通工程”的目标是使全省任何两个城镇间都可以实现交通（但不一定有直接的道路相连，只要互相间接通过道路可达即可）。问最少还需要建设多少条道路？&nbsp; 
     <br> 
    </div> 
    <div style="height:auto; margin:0px">
      &nbsp; 
    </div> <br> 
    <div style="height:38px; padding:0px 14px; color:rgb(124,169,237); font-size:18px; font-family:Arial; font-weight:bold">
      Input 
    </div> 
    <div style="height:auto; margin:0px; padding:0px 20px; font-size:14px; font-family:&quot;Times New Roman&quot;; text-align:left">
      测试输入包含若干测试用例。每个测试用例的第1行给出两个正整数，分别是城镇数目N ( &lt; 1000 )和道路数目M；随后的M行对应M条道路，每行给出一对正整数，分别是该条道路直接连通的两个城镇的编号。为简单起见，城镇从1到N编号。&nbsp; 
     <br> 注意:两个城市之间可以有多条道路相通,也就是说 
     <br> 3 3 
     <br> 1 2 
     <br> 1 2 
     <br> 2 1 
     <br> 这种输入也是合法的 
     <br> 当N为0时，输入结束，该用例不被处理。&nbsp; 
     <br> 
    </div> 
    <div style="height:auto; margin:0px">
      &nbsp; 
    </div> <br> 
    <div style="height:38px; padding:0px 14px; color:rgb(124,169,237); font-size:18px; font-family:Arial; font-weight:bold">
      Output 
    </div> 
    <div style="height:auto; margin:0px; padding:0px 20px; font-size:14px; font-family:&quot;Times New Roman&quot;; text-align:left">
      对每个测试用例，在1行里输出最少还需要建设的道路数目。&nbsp; 
     <br> 
    </div> 
    <div style="height:auto; margin:0px">
      &nbsp; 
    </div> <br> 
    <div style="height:38px; padding:0px 14px; color:rgb(124,169,237); font-size:18px; font-family:Arial; font-weight:bold">
      Sample Input 
    </div> 
    <div style="height:auto; margin:0px; padding:0px 20px; font-size:14px; font-family:&quot;Times New Roman&quot;; text-align:left"> 
     <pre style="word-wrap:break-word; white-space:pre-wrap; margin-top:0px; margin-bottom:0px">
      
       
      <div style="font-family:&quot;Courier New&quot;,Courier,monospace">
       
        
       4 2
1 3
4 3
3 3
1 2
1 3
2 3
5 2
1 2
3 5
999 0
0
      
       
      </div></pre> 
    </div> 
    <div style="height:auto; margin:0px">
      &nbsp; 
    </div> <br> 
    <div style="height:38px; padding:0px 14px; color:rgb(124,169,237); font-size:18px; font-family:Arial; font-weight:bold">
      Sample Output 
    </div> 
    <div style="height:auto; margin:0px; padding:0px 20px; font-size:14px; font-family:&quot;Times New Roman&quot;; text-align:left"> 
     <pre style="word-wrap:break-word; white-space:pre-wrap; margin-top:0px; margin-bottom:0px">
      
       
      <div style="font-family:&quot;Courier New&quot;,Courier,monospace">
       
        
       1
0
2
998
      
       
      </div></pre> 
    </div> </td> 
  </tr> 
 </tbody> 
</table>

#include<iostream> 
    using namespace std;
    int pre[1000];
    int find(int x)
    {
        int r = x;
        while(pre[r] != r)
        r = pre[r];
        int i=x;
        int j;
        while(i != r)
        {
            j = pre[i];
            pre[i] = r;
            i = j;
        }
        return r;
    }
    int main()
    {
        int n,total;
        while(cin>>n&&n)
        {
            total = n-1;
            for(int i=1;i<=n;i++)
            {
                pre[i] = i;
            }
    	int m;
            cin>>m;
            while(m--)
            {
    	    int p1,p2;
                cin>>p1>>p2;
    	    int f1,f2;
                f1 = find(p1);
                f2 = find(p2);
                if(f1 != f2)
                {
                    pre[f2] = f1;
                    total--;
                }
            }
            cout<<total<<"\n";
        }
        return 0;
    }

<table style="font-family:&quot;Times New Roman&quot;; word-wrap:break-word"> 
 <tbody> 
  <tr> 
   <td align="center"> <h1 style="color:rgb(26,92,200)">畅通工程</h1> <strong><span style="font-family:Arial; color:green">Time Limit: 4000/2000 MS (Java/Others)&nbsp;&nbsp;&nbsp;&nbsp;Memory Limit: 65536/32768 K (Java/Others)<br> Total Submission(s): 50426&nbsp;&nbsp;&nbsp;&nbsp;Accepted Submission(s): 26894<br> </span></strong><br> <br> 
    <div style="height:38px; padding:0px 14px; color:rgb(124,169,237); font-size:18px; font-family:Arial; font-weight:bold">
      Problem Description 
    </div> 
    <div style="height:auto; margin:0px; padding:0px 20px; font-size:14px; font-family:&quot;Times New Roman&quot;; text-align:left">
      某省调查城镇交通状况，得到现有城镇道路统计表，表中列出了每条道路直接连通的城镇。省政府“畅通工程”的目标是使全省任何两个城镇间都可以实现交通（但不一定有直接的道路相连，只要互相间接通过道路可达即可）。问最少还需要建设多少条道路？&nbsp; 
     <br> 
    </div> 
    <div style="height:auto; margin:0px">
      &nbsp; 
    </div> <br> 
    <div style="height:38px; padding:0px 14px; color:rgb(124,169,237); font-size:18px; font-family:Arial; font-weight:bold">
      Input 
    </div> 
    <div style="height:auto; margin:0px; padding:0px 20px; font-size:14px; font-family:&quot;Times New Roman&quot;; text-align:left">
      测试输入包含若干测试用例。每个测试用例的第1行给出两个正整数，分别是城镇数目N ( &lt; 1000 )和道路数目M；随后的M行对应M条道路，每行给出一对正整数，分别是该条道路直接连通的两个城镇的编号。为简单起见，城镇从1到N编号。&nbsp; 
     <br> 注意:两个城市之间可以有多条道路相通,也就是说 
     <br> 3 3 
     <br> 1 2 
     <br> 1 2 
     <br> 2 1 
     <br> 这种输入也是合法的 
     <br> 当N为0时，输入结束，该用例不被处理。&nbsp; 
     <br> 
    </div> 
    <div style="height:auto; margin:0px">
      &nbsp; 
    </div> <br> 
    <div style="height:38px; padding:0px 14px; color:rgb(124,169,237); font-size:18px; font-family:Arial; font-weight:bold">
      Output 
    </div> 
    <div style="height:auto; margin:0px; padding:0px 20px; font-size:14px; font-family:&quot;Times New Roman&quot;; text-align:left">
      对每个测试用例，在1行里输出最少还需要建设的道路数目。&nbsp; 
     <br> 
    </div> 
    <div style="height:auto; margin:0px">
      &nbsp; 
    </div> <br> 
    <div style="height:38px; padding:0px 14px; color:rgb(124,169,237); font-size:18px; font-family:Arial; font-weight:bold">
      Sample Input 
    </div> 
    <div style="height:auto; margin:0px; padding:0px 20px; font-size:14px; font-family:&quot;Times New Roman&quot;; text-align:left"> 
     <pre style="word-wrap:break-word; white-space:pre-wrap; margin-top:0px; margin-bottom:0px">
       
        
      <div style="font-family:&quot;Courier New&quot;,Courier,monospace">
       
         
        4 2
1 3
4 3
3 3
1 2
1 3
2 3
5 2
1 2
3 5
999 0
0
       
        
      </div></pre> 
    </div> 
    <div style="height:auto; margin:0px">
      &nbsp; 
    </div> <br> 
    <div style="height:38px; padding:0px 14px; color:rgb(124,169,237); font-size:18px; font-family:Arial; font-weight:bold">
      Sample Output 
    </div> 
    <div style="height:auto; margin:0px; padding:0px 20px; font-size:14px; font-family:&quot;Times New Roman&quot;; text-align:left"> 
     <pre style="word-wrap:break-word; white-space:pre-wrap; margin-top:0px; margin-bottom:0px">
       
        
      <div style="font-family:&quot;Courier New&quot;,Courier,monospace">
       
         
        1
0
2
998
       
        
      </div></pre> 
    </div> </td> 
  </tr> 
 </tbody> 
</table>