1034. Head of a Gang (30)

分析：

　　考察并查集，注意中间合并时的时间的合并和人数的合并。

#include <iostream>
#include <stdio.h>
#include <algorithm>
#include <cstring>
#include <string>
#include <vector>
#include <cctype>
#include <map>

using namespace std;

const int Max_Int = 0x7fffffff;
const int Max_required = 500;

struct Node                    //记录gang的信息
{
    int total_person;        //gang中总人数
    int time_length;        //gang中总时间
    int tree;                //并查集用处
}gang[2005];            

struct Name
{
    char ch[5];
};

map<string, int> Map_Name2int;        //名字转下标之用
map<int, string> Map_int2Name;
int _index;

int perp[2005];        //记录每个人花的时间

void Init()
{
    Map_Name2int.clear();
    _index = 0;
    for (int i = 0; i <= 2000; i++)
    {
        gang[i].total_person = 1;
        gang[i].tree = i;
        gang[i].time_length = 0;
        perp[i] = 0;
    }
}


int string2index(string name)
{
    map<string, int>::iterator iter = Map_Name2int.find(name);
    if (iter != Map_Name2int.end())
        return iter->second;
    Map_Name2int.insert(make_pair(name, _index));
    Map_int2Name.insert(make_pair(_index, name));
    _index++;

    return _index - 1;
}

int get_root(int r)
{
    while (r != gang[r].tree)
        r = gang[r].tree;
    return r;
}

//-------------------------------------------------
void merge(int fir, int sec, int time)  //合并操作。
{
    fir = get_root(fir);
    sec = get_root(sec);

    if (fir != sec)                    //如果两个拥有不同的根
    {
        gang[sec].tree = fir;
        gang[fir].time_length += time + gang[sec].time_length;
        gang[fir].total_person += gang[sec].total_person;
    }
    else 
        gang[fir].time_length += time;
    //cout << gang[fir].total_person << " " << gang[fir].time_length << endl;
}

    
struct Gang                 //以root为首的群的head，存储答案
{
    int head;
    int root;
    string name;
}gang_head[1000];
int total_gang;

void find_head(int k)
{
    total_gang = 0;
    for (int i = 0; i < _index; i++)
    {
        int r = get_root(i);

        //cout << r << " " << Map_int_Name.find(i)->second << endl;

        if (gang[r].total_person > 2 && gang[r].time_length > k)
        {
            bool flag = 0;
            for (int j = 0; j < total_gang; j++)
            {
                if (gang_head[j].root == r)
                {
                    flag = 1;
                    if (perp[gang_head[j].head] < perp[i])
                        gang_head[j].head = i;
                    break;
                }
            }

            if (flag == 0)
            {
                gang_head[total_gang].head = i;
                gang_head[total_gang].root = r;
                total_gang++;
            }
        }
    }
}

int cmp(const Gang &a, const Gang &b)
{
    return a.name < b.name;
}

void print_info()
{
    for (int i = 0; i < total_gang; i++)
        gang_head[i].name = Map_int2Name.find(gang_head[i].head)->second;

    sort(gang_head, gang_head + total_gang, cmp);

    printf("%d\n", total_gang);
    for (int i = 0; i < total_gang; i++)
    {
        cout << gang_head[i].name << " " << gang[gang_head[i].root].total_person << endl;
    }

}

int main()
{
    int n, k;

    while (scanf("%d%d", &n, &k) != EOF)
    {

        Init();                //初始化

        string name1, name2;
        int time;
        while (n--)
        {
            cin >> name1 >> name2 >> time;
            int fir = string2index(name1);
            int sec = string2index(name2);

            perp[fir] += time;
            perp[sec] += time;
            merge(fir, sec, time);
        } 

        find_head(k);

        print_info();
    }
    return 0;
}