OJ-Problems-Source/HDOJ/2962_autoAC.cpp
2016-08-24 18:27:13 +08:00

87 lines
2.1 KiB
C++

#include <iostream>
#include <cstdlib>
#include <cstdio>
#include <cstring>
#include <queue>
using namespace std;
const int SIZE = 10010;
const int INF = 0xfffffff;
int u[5*SIZE], v[5*SIZE], w[5*SIZE], nex[5*SIZE], h[5*SIZE];
int first[SIZE], d[SIZE];
int n, m, cnt;
int s, e;
void read_graph(int u1, int v1, int w1, int h1)
{
u[cnt] = u1; v[cnt] = v1; w[cnt] = w1; h[cnt] = h1;
nex[cnt] = first[u[cnt]];
first[u[cnt]] = cnt++;
}
int spfa(int src, int mid)
{
queue<int> q;
bool inq[SIZE] = {0};
for(int i = 1; i <= n; i++) d[i] = (i == src)?0:INF;
q.push(src);
while(!q.empty())
{
int x = q.front(); q.pop();
inq[x] = 0;
for(int e = first[x]; e!=-1; e = nex[e]) if(d[v[e]] > d[x]+w[e] && mid <= h[e])
{
d[v[e]] = d[x] + w[e];
if(!inq[v[e]])
{
inq[v[e]] = 1;
q.push(v[e]);
}
}
}
if(d[e] == INF) return 0;
return 1;
}
void init()
{
memset(first, -1, sizeof(first));
cnt = 0;
}
int main()
{
int times = 0;
while(~scanf("%d%d", &n, &m), n, m)
{
init();
while(m--)
{
int u1, v1, w1, h1;
scanf("%d%d%d%d", &u1, &v1, &h1, &w1);
if(h1 == -1) h1 = INF;
read_graph(u1, v1, w1, h1);
read_graph(v1, u1, w1, h1);
}
int x = 0, y, ans = INF, mid, h;
scanf("%d%d%d", &s, &e, &y);
while(x <= y)
{
mid = (x+y)>>1;
if(spfa(s, mid))
{
x = mid+1;
ans = d[e];
h = mid;
}
else y = mid-1;
}
if(times) printf("\n");
printf("Case %d:\n", ++times);
if(ans != INF)
{
printf("maximum height = %d\n", h);
printf("length of shortest route = %d\n", ans);
}
else
{
printf("cannot reach destination\n");
}
}
}