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
原文地址:https://www.cnblogs.com/xiaoyesoso/p/4249344.html