mirror of
https://github.com/Kiritow/OJ-Problems-Source.git
synced 2024-03-22 13:11:29 +08:00
114 lines
2.4 KiB
C++
114 lines
2.4 KiB
C++
#include<iostream>
|
|
#include<vector>
|
|
#include<string.h>
|
|
using namespace std;
|
|
int map[1005][1005];
|
|
int pre[1005];
|
|
int dis[1005];
|
|
bool s[1005];
|
|
class path
|
|
{
|
|
public:
|
|
int start, end;
|
|
};
|
|
vector<path>p;
|
|
void dijkstra(int n)
|
|
{
|
|
memset(s,false,sizeof(s));
|
|
int i, j, k;
|
|
for (i = 2; i <= n; i++)
|
|
{
|
|
dis[i] = map[1][i];
|
|
if (map[1][i] != -1)
|
|
{
|
|
pre[i] = 1;
|
|
}
|
|
else
|
|
{
|
|
pre[i] = -1;
|
|
}
|
|
}
|
|
pre[1] = -1;
|
|
dis[1] = 0;
|
|
s[1] = true;
|
|
for (j = 2; j <= n; j++)
|
|
{
|
|
int min = 100000;
|
|
int u;
|
|
for (i = 1; i <= n; i++)
|
|
{
|
|
if (!s[i] && dis[i] != -1)
|
|
{
|
|
if (min > dis[i])
|
|
{
|
|
min = dis[i];
|
|
u = i;
|
|
}
|
|
}
|
|
}
|
|
s[u] = true;
|
|
for (k = 1; k <= n;k++)
|
|
{
|
|
if (!s[k] && map[u][k]!=-1)
|
|
{
|
|
if ((dis[k] > dis[u] + map[u][k])||dis[k]==-1)
|
|
{
|
|
dis[k] = dis[u] + map[u][k];
|
|
pre[k] = u;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
void findpath(int n)
|
|
{
|
|
p.clear();
|
|
int i = n;
|
|
while (pre[i]!=-1)
|
|
{
|
|
path tmp;
|
|
tmp.start = pre[i];
|
|
tmp.end = i;
|
|
p.push_back(tmp);
|
|
i=pre[i];
|
|
}
|
|
}
|
|
int main()
|
|
{
|
|
int n, m;
|
|
while (cin>>n>>m)
|
|
{
|
|
int i,k;
|
|
int start, end, weight;
|
|
for (i = 1; i <= n;i++)
|
|
for (k = 1; k <= n; k++)
|
|
{
|
|
map[i][k] = -1;
|
|
}
|
|
for (i = 0; i < m; i++)
|
|
{
|
|
cin >> start >> end >> weight;
|
|
map[start][end] = weight;
|
|
map[end][start] = weight;
|
|
}
|
|
dijkstra(n);
|
|
findpath(n);
|
|
int num,max=-1;
|
|
for (num = 0; num < p.size(); num++)
|
|
{
|
|
path tmp = p[num];
|
|
int t;
|
|
t = map[tmp.start][tmp.end];
|
|
map[tmp.start][tmp.end] = -1;
|
|
map[tmp.end][tmp.start] = -1;
|
|
dijkstra(n);
|
|
if (dis[n]>max)
|
|
max = dis[n];
|
|
map[tmp.start][tmp.end] = t;
|
|
map[tmp.end][tmp.start] = t;
|
|
}
|
|
cout << max << endl;
|
|
}
|
|
return 0;
|
|
}
|