• Head of a Gang (map+邻接表+DFS)


    One way that the police finds the head of a gang is to check people's phone calls. If there is a phone call between A and B, we say that A and B is related. The weight of a relation is defined to be the total time length of all the phone calls made between the two persons. A "Gang" is a cluster of more than 2 persons who are related to each other with total relation weight being greater than a given threshold K. In each gang, the one with maximum total weight is the head. Now given a list of phone calls, you are supposed to find the gangs and the heads.

     Input Specification:

    Each input file contains one test case. For each case, the first line contains two positive numbers N and K (both less than or equal to 1000), the number of phone calls and the weight threthold, respectively. Then N lines follow, each in the following format:

    Name1 Name2 Time

    where Name1 and Name2 are the names of people at the two ends of the call, and Time is the length of the call. A name is a string of three capital letters chosen from A-Z. A time length is a positive integer which is no more than 1000 minutes.

     Output Specification:

    For each test case, first print in a line the total number of gangs. Then for each gang, print in a line the name of the head and the total number of the members. It is guaranteed that the head is unique for each gang. The output must be sorted according to the alphabetical order of the names of the heads.

    Sample Input 1:

    8 59

    AAA BBB 10

    BBB AAA 20

    AAA CCC 40

    DDD EEE 5

    EEE DDD 70

    FFF GGG 30

    GGG HHH 20

    HHH FFF 10

     Sample Output 1:

    2

    AAA 3

    GGG 3

     Sample Input 2:

    8 70

    AAA BBB 10

    BBB AAA 20

    AAA CCC 40

    DDD EEE 5

    EEE DDD 70

    FFF GGG 30

    GGG HHH 20

    HHH FFF 10

     Sample Output 2:

    0

    首先 要建一个 以string的 下标的 连接表,需要用map

     map<string,vector<string>  > mm;

    表内直接存放 string 地址就行了,权值另外保存

     map<string,int> node;

    再 DFS  求出极大连通图的个数,及各各极大连通图的节点数,权值之和,权值最大的节点地址

    坑点:

    1、“A "Gang" is a cluster of more than 2 persons ”  所以节点数要大于2

    2、因为每次通话每个人都权值都加了,其实总通话时间=权值之和/2;

      1 #include <iostream>
      2 
      3 #include <string>
      4 
      5 #include <vector>
      6 
      7 #include <map>
      8 
      9 using namespace std;
     10 
     11  
     12 
     13 struct Gang
     14 
     15 {
     16 
     17    int num,sum;
     18 
     19 };
     20 
     21  
     22 
     23 string ss1[1001];
     24 
     25 string ss2[1001];
     26 
     27  
     28 
     29    map<string,vector<string>  > mm;
     30 
     31        map<string,int> visit;
     32 
     33        map<string,int> node;
     34 
     35          map<string,Gang> result;
     36 
     37  
     38 
     39 void DFS(string s,int &sum,string &max,int &num)
     40 
     41 {
     42 
     43    if(node[s]>node[max]) max=s;
     44 
     45     num++;
     46 
     47       sum=sum+node[s];
     48 
     49    visit[s]=1;
     50 
     51   
     52 
     53    for(int i=0;i<mm[s].size();i++)
     54 
     55       {
     56 
     57             if(visit[mm[s][i]]==0)
     58 
     59                   DFS(mm[s][i],sum,max,num);
     60 
     61       }
     62 
     63    
     64 
     65 }
     66 
     67  
     68 
     69  
     70 
     71 int main()
     72 
     73 {
     74 
     75  
     76 
     77      int  n,k,t;
     78 
     79       string s1,s2;
     80 
     81       while(cin>>n)
     82 
     83       {
     84 
     85          cin>>k;
     86 
     87       
     88 
     89          mm.clear();
     90 
     91          visit.clear();
     92 
     93          node.clear();
     94 
     95          result.clear();
     96 
     97  
     98 
     99      
    100 
    101  
    102 
    103          int i;
    104 
    105  
    106 
    107          for(i=0;i<n;i++)
    108 
    109          {
    110 
    111             cin>>s1>>s2>>t;
    112 
    113               ss1[i]=s1;
    114 
    115               ss2[i]=s2;
    116 
    117               visit[s1]=0;
    118 
    119               visit[s2]=0;
    120 
    121               node[s1]+=t;
    122 
    123               node[s2]+=t;
    124 
    125                mm[s1].push_back(s2);
    126 
    127                mm[s2].push_back(s1);
    128 
    129          }
    130 
    131  
    132 
    133  
    134 
    135          map<string,int>::iterator it;
    136 
    137          int num;
    138 
    139          int sum;
    140 
    141          int count=0;
    142 
    143          string max;
    144 
    145         
    146 
    147          for(it=node.begin();it!=node.end();it++)
    148 
    149          {
    150 
    151                if(visit[it->first]==0)
    152 
    153                {
    154 
    155                     
    156 
    157                      sum=0;
    158 
    159                      num=0;
    160 
    161                      max=it->first;
    162 
    163                      DFS(it->first,sum,max,num);
    164 
    165                      if(sum/2>k&&num>2)
    166 
    167                      {
    168 
    169                  count++;
    170 
    171                        result[max].num=num;
    172 
    173                        result[max].sum=sum;
    174 
    175                      }
    176 
    177  
    178 
    179                }
    180 
    181          }
    182 
    183  
    184 
    185          cout<<count<<endl;
    186 
    187          map<string,Gang>::iterator it2;
    188 
    189          for(it2=result.begin();it2!=result.end();it2++)
    190 
    191          {
    192 
    193                cout<<it2->first<<" "<<(it2->second).num<<endl;
    194 
    195          }        
    196 
    197       }
    198 
    199   return 0;
    200 
    201 }
    View Code
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  • 原文地址:https://www.cnblogs.com/xiaoyesoso/p/4249344.html
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