POJ 3635 Full Tank? 拆点建图+dijkstra

#include <cstdio>
#include <cstring>
#include <queue>
using namespace std;
#define fst first
#define snd second
typedef pair<int, int> pii;
const int maxn=1005;
const int maxv=133333;
const int maxm=2333333;
const int inf=0x3f3f3f3f;
int tot;
struct Edge {
int to, cost, next;
} edge[maxm];
int head[maxm];
void addedge(int u, int v, int w) {
edge[tot].to=v;
edge[tot].cost=w;
edge[tot].next=head[u];
head[u]=tot++;
}
int V, n, m, K;
int tank, s, t;
int d[maxv], pri[maxn], u[maxm], v[maxm], w[maxm];
void dijkstra(int s) {
priority_queue<pii, vector<pii>, greater<pii> > que;
memset(d, 0x3f, sizeof d);
d[s]=0;
que.push(pii(0, s));
while (!que.empty()) {
pii p=que.top();
que.pop();
int v=p.snd;
if (d[v]<p.fst)
continue;
// 不加会T
if (v==t*101)
break;
for (int i=head[v]; i!=-1; i=edge[i].next) {
int to=edge[i].to, cost=edge[i].cost;
if (v%101>tank)
continue;
if (d[to]>d[v]+cost) {
d[to]=d[v]+cost;
que.push(pii(d[to], to));
}
}
}
}
int main()
{
//freopen("in.txt", "r", stdin);
while (scanf("%d%d", &n, &m)==2) {
for (int i=0; i<n; i++)
scanf("%d", &pri[i]);
for (int i=0; i<m; i++)
scanf("%d%d%d", &u[i], &v[i], &w[i]);
tot=0;
memset(head, -1, sizeof head);
for (int i=0; i<n; i++)
for (int j=0; j<100; j++)
addedge(101*i+j, 101*i+j+1, pri[i]);
for (int i=0; i<m; i++)
for (int j=w[i]; j<=100; j++) {
addedge(101*u[i]+j, 101*v[i]+j-w[i], 0);
addedge(101*v[i]+j, 101*u[i]+j-w[i], 0);
}
scanf("%d", &K);
for (int i=0; i<K; i++) {
scanf("%d%d%d", &tank, &s, &t);
dijkstra(s*101);
if (d[t*101]==inf)
puts("impossible");
else
printf("%d\n", d[t*101]);
}
}
return 0;
}