PAT甲级题——1003 Emergency (25 分)【求最短路径的条数+DFS/Dijsktra】

As an emergency rescue team leader of a city, you are given a special map of your country. The map shows several scattered cities connected by some roads. Amount of rescue teams in each city and the length of each road between any pair of cities are marked on the map. When there is an emergency call to you from some other city, your job is to lead your men to the place as quickly as possible, and at the mean time, call up as many hands on the way as possible.

Input Specification:

Each input file contains one test case. For each test case, the first line contains 4 positive integers: N (≤500) - the number of cities (and the cities are numbered from 0 to N−1), M - the number of roads, C​1​​ and C​2​​ - the cities that you are currently in and that you must save, respectively. The next line contains N integers, where the i-th integer is the number of rescue teams in the i-th city. Then M lines follow, each describes a road with three integers c​1​​, c​2​​ and L, which are the pair of cities connected by a road and the length of that road, respectively. It is guaranteed that there exists at least one path from C​1​​ to C​2​​.

Output Specification:

For each test case, print in one line two numbers: the number of different shortest paths between C​1​​ and C​2​​, and the maximum amount of rescue teams you can possibly gather. All the numbers in a line must be separated by exactly one space, and there is no extra space allowed at the end of a line.

Sample Input:

5 6 0 2
1 2 1 5 3
0 1 1
0 2 2
0 3 1
1 2 1
2 4 1
3 4 1

Sample Output:

2 4

题意：

这里的意思就是有n个城市，m条路，每个城市都有一些人数，每条路都有起点，终点，长度

这里让你求连接start和end两个城市的最短路径的个数，和这些路径中能收集的人数的最大值 

DFS写法：

#include
using namespace std;
const int INF = 999999;
int n,m,st,ed;
int wei[505],vis[505];
int mp[505][505];
int x,y,tmp;
int temp=INF;
int count,Max_num;
void init(){
	for(int i=0;iMax_num){
				Max_num=weight;
			}
		}
		return ;
	}
	if(len>temp)//没有这个剪枝，最后一个点会超时 
	    return ;
	for(int i=0;i>n>>m>>st>>ed;
	init();
	for(int i=0;i>wei[i];
	}
	for(int i=0;i>x>>y>>tmp;
		mp[x][y]=mp[y][x]=tmp;
	}
	dfs(st,ed,0,wei[st]);
	cout<

Dijsktra写法：（还有bug,未完待续）

#include
#include
using namespace std;
const int INF=9999999;
int n,m,st,ed;
int wei[505],vis[505],dis[505],count[505],num[505];
int mp[505][505];
int x,y,d;
void Dijsktra(){
	memset(dis,sizeof(dis),INF);
	dis[st]=0;
	count[st]=1;
	num[st]=wei[st];
	
	for(int i=0;i>n>>m>>st>>ed;
	for(int i=0;i>wei[i];
	}
	for(int i=0;i>x>>y>>d;
		mp[x][y]=mp[y][x]=d;
	}
	Dijsktra();
	cout<