// aiqiyi.cpp: 定义控制台应用程序的入口点。
//
#include "stdafx.h"
using namespace std;
class Node
{
public:
int index;
int parent;
vector<int> next;
int dist;
Node(int val_index, int par, vector<int> nex, int val_dist) :
index(val_index), parent(par), next(nex), dist(val_dist) {}
};
int main()
{
int Farm_Num;
int r_data,pc = 0,farm_num_temp,sign = 0;//sign:0--read farm_num;1--read farm_strucutre;2--read farm_route;3--read farm--hole
vector<vector<int> > Farm_Structure;//[i][0]:node_num,[i][1]:route_num,[i][2]:hole_num
vector<vector<Node*> >Farm_Node;//[i]:the node set of farm[i]
vector<vector<vector<int> > >Route;//[i]:the route set of farm(graph)[i]
vector<vector<vector<int> > >Hole;//[i]:the hole set of farm[i]
vector<map<pair<int,int>,int> >Way;//[i]:the way set of farm[i]---in this set, each edge's weight is the minimal number of all edges appearing in route/hole set
//get data from cin buffer
while (cin >> r_data)
{
//to get the number of graphs
if (!pc)
{
Farm_Num = r_data;
farm_num_temp = Farm_Num;
sign = 1;
}
else if(sign == 1)//read farm_structure
{
farm_num_temp--;
vector<int>farm_str_temp;
farm_str_temp.push_back(r_data);
for (int f_i = 0; f_i < 2; ++f_i)
{
cin >> r_data;
pc++;
farm_str_temp.push_back(r_data);
}
Farm_Structure.push_back(farm_str_temp);
if (farm_str_temp[1])//route set exists
sign = 2;
else
sign = 3;
}
else if (sign == 2)//read route_set
{
vector<vector<int> >farm_rou_graph;
vector<int>farm_rou_temp(3,0);
farm_rou_temp[0] = r_data;
for (int r_i = 0; r_i < (*(Farm_Structure.end() - 1))[1] * 3 - 1; ++r_i)
{
cin >> r_data;
pc++;
farm_rou_temp[(r_i + 1) % 3] = r_data;
if (r_i % 3 == 1)
farm_rou_graph.push_back(farm_rou_temp);
}
Route.push_back(farm_rou_graph);
if ((*(Farm_Structure.end() - 1))[2])//hole_set exists
sign = 3;
else
sign = 1;
}
else //sign == 3:read hole_set
{
vector<vector<int> >farm_hol_graph;
vector<int>farm_hol_temp(3, 0);
farm_hol_temp[0] = -r_data;
for (int h_i = 0; h_i < (*(Farm_Structure.end() - 1))[2] * 3 - 1; ++h_i)
{
cin >> r_data;
pc++;
farm_hol_temp[(h_i + 1) % 3] = -r_data;
if (h_i % 3 == 1)
farm_hol_graph.push_back(farm_hol_temp);
}
Hole.push_back(farm_hol_graph);
if (farm_num_temp)// begin to read data again
sign = 1;
else
break;
}
pc++;
}
//modify Way set
for (int g_i = 0; g_i < Farm_Num; ++g_i)
{
map<pair<int,int>, int> way_temp;
for (int r_i = 0; r_i < Farm_Structure[g_i][1]; ++r_i)//bidirectional weight
{
auto f_sign = way_temp.find({ Route[g_i][r_i][0]-1,Route[g_i][r_i][1]-1 });
if (f_sign == way_temp.end())//not exist
way_temp[{ Route[g_i][r_i][0]-1, Route[g_i][r_i][1]-1 }] = Route[g_i][r_i][2];
else
way_temp[{ Route[g_i][r_i][0]-1, Route[g_i][r_i][1]-1 }] = min(Route[g_i][r_i][2], way_temp[{ Route[g_i][r_i][0]-1, Route[g_i][r_i][1]-1 }]);
auto g_sign = way_temp.find({ Route[g_i][r_i][1]-1,Route[g_i][r_i][0]-1 });
if (g_sign == way_temp.end())//already exist
way_temp[{ Route[g_i][r_i][1]-1, Route[g_i][r_i][0]-1 }] = Route[g_i][r_i][2];
else
way_temp[{ Route[g_i][r_i][1]-1, Route[g_i][r_i][0]-1 }] = min(Route[g_i][r_i][2], way_temp[{ Route[g_i][r_i][1]-1, Route[g_i][r_i][0]-1 }]);
}
for (int h_i = 0; h_i < Farm_Structure[g_i][2]; ++h_i)
{
auto f_sign = way_temp.find({ -Hole[g_i][h_i][0]-1,-Hole[g_i][h_i][1]-1 });
if (f_sign == way_temp.end())//already exist
way_temp[{ -Hole[g_i][h_i][0]-1, -Hole[g_i][h_i][1]-1 }] = Hole[g_i][h_i][2];
else
way_temp[{ -Hole[g_i][h_i][0]-1, -Hole[g_i][h_i][1]-1 }] = min(Hole[g_i][h_i][2], way_temp[{ -Hole[g_i][h_i][0]-1, -Hole[g_i][h_i][1]-1 }]);
}
Way.push_back(way_temp);
}
//generate graph
for (int G_i = 0; G_i < Farm_Num; ++G_i)
{
vector<Node*> Farm_Node_temp;
for (int n_i = 0; n_i < Farm_Structure[G_i][0]; ++n_i)
{
Farm_Node_temp.push_back(new Node(n_i, -1, vector<int>(), INT_MAX));//note that the index of node starts at 0
}
for (auto R_i = Way[G_i].begin(); R_i != Way[G_i].end(); ++R_i)
{
((Farm_Node_temp[(R_i->first).first])->next).push_back((R_i->first).second);
}
Farm_Node.push_back(Farm_Node_temp);
}
//Bellman-Ford Algorithm
for (int g_i = 0; g_i < Farm_Num; ++g_i)
{
Farm_Node[g_i][0]->dist = 0;
for (int v_i = 0; v_i < Farm_Structure[g_i][0] - 1; ++v_i)
{
for (auto r_i = Way[g_i].begin(); r_i != Way[g_i].end(); ++r_i)
{
//relax edge r_i
if (Farm_Node[g_i][(r_i->first).second]->dist > (Farm_Node[g_i][(r_i->first).first]->dist) + r_i->second)
{
Farm_Node[g_i][(r_i->first).second]->dist = (Farm_Node[g_i][(r_i->first).first]->dist) + r_i->second;
Farm_Node[g_i][(r_i->first).second]->parent = (r_i->first).first;
}
}
}
int print_sign = 0;
for (auto r_j = Way[g_i].begin(); r_j != Way[g_i].end(); ++r_j)
{
if (Farm_Node[g_i][(r_j->first).second]->dist > (Farm_Node[g_i][(r_j->first).first]->dist) + r_j->second)
{
print_sign = 1;
break;
}
}
if (print_sign)
cout << "YES" << endl;
else
cout << "NO" << endl;
}
return 0;
}// stdafx.h : 标准系统包含文件的包含文件，
// 或是经常使用但不常更改的
// 特定于项目的包含文件
//
#include "targetver.h"
#include<algorithm>
#include<iostream>
#include<map>
#include<vector>
// TODO: 在此处引用程序需要的其他头文件然而poj不支持map的高级一些的功能，所以编译一直无法通过…
然后修改了一下，结果超时了。。。
这是新版的：
#include"iostream"
using namespace std;
#define inf 1e10
int dist[1005];
struct edge
{
int stat, endi, weig;
}Edge[5200];
int num_node, num_pos, num_neg;
bool bellman(int pc)
{
bool flag;
for (int i = 0; i < num_node - 1; i++)
{
flag = false;
for (int j = 0; j < pc; j++)
{
if (dist[Edge[j].endi] > dist[Edge[j].stat] + Edge[j].weig)
{
dist[Edge[j].endi] = dist[Edge[j].stat] + Edge[j].weig;
flag = true;
}
}
if (!flag)
break;
}
for (int i = 0; i < pc; i++)
{
if (dist[Edge[i].endi] > dist[Edge[i].stat] + Edge[i].weig)
return true;
}
return false;
}
int main()
{
int N;
cin>>N;
while (N--)
{
memset(dist, inf, sizeof(dist));
cin >> num_node >> num_pos >> num_neg;
int pc = 0;
for (int i = 1; i <= num_pos; i++)
{
int u, v, w;
cin >> u >> v >> w;
Edge[pc].stat = Edge[pc + 1].endi = u;
Edge[pc].endi = Edge[pc + 1].stat = v;
Edge[pc++].weig = w;
Edge[pc++].weig = w;
}
for (int j = 1; j <= num_neg; j++)
{
int u, v, w;
cin >> u >> v >> w;
Edge[pc].stat = u;
Edge[pc].endi = v;
Edge[pc++].weig = -w;
}
if (bellman(pc))
cout << "YES" << endl;
else
cout << "NO" << endl;
}
} 附上超时版本（个人认为更鲁棒啊）：
// aiqiyi.cpp: 定义控制台应用程序的入口点。
//
#include "stdafx.h"
using namespace std;
#define INT_MAX 1e10
class Node
{
public:
int index;
vector<int> next;
int dist;
Node(int val_index,vector<int> nex, int val_dist) :
index(val_index), next(nex), dist(val_dist) {}
};
string convert(int n)
{
string res = "";
if (n == 0)
return "0";
while (n)
{
res += char(n % 10+'0');
n /= 10;
}
return res;
}
string trans(int x, int y)
{
return convert(x) + '+' + convert(y);
}
vector<int>TRANS(string s)
{
vector<int>res(2, 0);
int len = s.size(),sign = 0;
for (int i = 0; i < len; ++i)
{
if (s[i] != '+')
{
res[sign] *= 10;
res[sign] += s[i] - '0';
}
else
sign++;
}
return res;
}
int main()
{
int Farm_Num;
int r_data,pc = 0,farm_num_temp,sign = 0;
vector<vector<int> > Farm_Structure;
vector<vector<Node*> >Farm_Node;
vector<vector<vector<int> > >Route;
vector<vector<vector<int> > >Hole;
vector<map<string,int> >Way;
while (cin >> r_data)
{
if (!pc)
{
Farm_Num = r_data;
farm_num_temp = Farm_Num;
sign = 1;
}
else if(sign == 1)
{
farm_num_temp--;
vector<int>farm_str_temp;
farm_str_temp.push_back(r_data);
for (int f_i = 0; f_i < 2; ++f_i)
{
cin >> r_data;
pc++;
farm_str_temp.push_back(r_data);
}
Farm_Structure.push_back(farm_str_temp);
if (farm_str_temp[1])//route set exists
sign = 2;
else
sign = 3;
}
else if (sign == 2)//read route_set
{
vector<vector<int> >farm_rou_graph;
vector<int>farm_rou_temp(3,0);
farm_rou_temp[0] = r_data;
for (int r_i = 0; r_i < (*(Farm_Structure.end() - 1))[1] * 3 - 1; ++r_i)
{
cin >> r_data;
pc++;
farm_rou_temp[(r_i + 1) % 3] = r_data;
if (r_i % 3 == 1)
farm_rou_graph.push_back(farm_rou_temp);
}
Route.push_back(farm_rou_graph);
if ((*(Farm_Structure.end() - 1))[2])//hole_set exists
sign = 3;
else
sign = 1;
}
else //sign == 3:read hole_set
{
vector<vector<int> >farm_hol_graph;
vector<int>farm_hol_temp(3, 0);
farm_hol_temp[0] = -r_data;
for (int h_i = 0; h_i < (*(Farm_Structure.end() - 1))[2] * 3 - 1; ++h_i)
{
cin >> r_data;
pc++;
farm_hol_temp[(h_i + 1) % 3] = -r_data;
if (h_i % 3 == 1)
farm_hol_graph.push_back(farm_hol_temp);
}
Hole.push_back(farm_hol_graph);
if (farm_num_temp)// begin to read data again
sign = 1;
else
break;
}
pc++;
}
//modify Way set
for (int g_i = 0; g_i < Farm_Num; ++g_i)
{
map<string, int> way_temp;
for (int r_i = 0; r_i < Farm_Structure[g_i][1]; ++r_i)//bidirectional weight
{
map<string,int>::iterator f_sign = way_temp.find(trans(Route[g_i][r_i][0]-1,Route[g_i][r_i][1]-1));
if (f_sign == way_temp.end())//not exist
way_temp[trans( Route[g_i][r_i][0]-1, Route[g_i][r_i][1]-1 )] = Route[g_i][r_i][2];
else
way_temp[trans( Route[g_i][r_i][0]-1, Route[g_i][r_i][1]-1 )] = min(Route[g_i][r_i][2], way_temp[trans( Route[g_i][r_i][0]-1, Route[g_i][r_i][1]-1 )]);
map<string, int>::iterator g_sign = way_temp.find(trans( Route[g_i][r_i][1]-1,Route[g_i][r_i][0]-1 ));
if (g_sign == way_temp.end())//already exist
way_temp[trans( Route[g_i][r_i][1]-1, Route[g_i][r_i][0]-1 )] = Route[g_i][r_i][2];
else
way_temp[trans( Route[g_i][r_i][1]-1, Route[g_i][r_i][0]-1 )] = min(Route[g_i][r_i][2], way_temp[trans( Route[g_i][r_i][1]-1, Route[g_i][r_i][0]-1 )]);
}
for (int h_i = 0; h_i < Farm_Structure[g_i][2]; ++h_i)
{
map<string, int>::iterator f_sign = way_temp.find(trans( -Hole[g_i][h_i][0]-1,-Hole[g_i][h_i][1]-1 ));
if (f_sign == way_temp.end())//already exist
way_temp[trans( -Hole[g_i][h_i][0]-1, -Hole[g_i][h_i][1]-1 )] = Hole[g_i][h_i][2];
else
way_temp[trans( -Hole[g_i][h_i][0]-1, -Hole[g_i][h_i][1]-1 )] = min(Hole[g_i][h_i][2], way_temp[trans( -Hole[g_i][h_i][0]-1, -Hole[g_i][h_i][1]-1 )]);
}
Way.push_back(way_temp);
}
//generate graph
for (int G_i = 0; G_i < Farm_Num; ++G_i)
{
vector<Node*> Farm_Node_temp;
for (int n_i = 0; n_i < Farm_Structure[G_i][0]; ++n_i)
{
Farm_Node_temp.push_back(new Node(n_i, vector<int>(), INT_MAX));//note that the index of node starts at 0
}
for (map<string, int>::iterator R_i = Way[G_i].begin(); R_i != Way[G_i].end(); ++R_i)
{
vector<int> temp_trans = TRANS(R_i->first);
((Farm_Node_temp[temp_trans[0]])->next).push_back(temp_trans[1]);
}
Farm_Node.push_back(Farm_Node_temp);
}
//Bellman-Ford Algorithm
for (int g_i = 0; g_i < Farm_Num; ++g_i)
{
bool flag;
Farm_Node[g_i][0]->dist = 0;
for (int v_i = 0; v_i < Farm_Structure[g_i][0] - 1; ++v_i)
{
flag = false;
for (map<string, int>::iterator r_i = Way[g_i].begin(); r_i != Way[g_i].end(); ++r_i)
{
vector<int> temp_t = TRANS(r_i->first);
//relax edge r_i
if (Farm_Node[g_i][temp_t[1]]->dist > (Farm_Node[g_i][temp_t[0]]->dist) + r_i->second)
{
Farm_Node[g_i][temp_t[1]]->dist = (Farm_Node[g_i][temp_t[0]]->dist) + r_i->second;
flag = true;
}
}
if (!flag)
break;
}
for (map<string, int>::iterator r_j = Way[g_i].begin(); r_j != Way[g_i].end(); ++r_j)
{
vector<int> temp_t = TRANS(r_j->first);
if (Farm_Node[g_i][temp_t[1]]->dist > (Farm_Node[g_i][temp_t[0]]->dist) + r_j->second)
{
flag = true;
break;
}
}
if (flag)
cout << "YES" << endl;
else
cout << "NO" << endl;
}
}