hdu 2066 一个人的旅行 (dij+heap)

Problem - 2066

　　入门SP，用dij+heap 0ms通过。

#define REP(i, n) for (int i = 0; i < (n); i++)
#define REP_1(i, n) for (int i = 1; i <= (n); i++)
typedef pair<LL, int> PLI;
#define PB push_back
#define MPR make_pair
#define FI first
#define SE second

VPII rel[N];
LL dis[N];
multiset<PLI> HP;

void input(int n, int s, int t) {
    REP(i, 1002) rel[i].clear(), dis[i] = linf;
    HP.clear();
    int a, b, d;
    REP(i, n) {
        scanf("%d%d%d", &a, &b, &d);
        rel[a].PB(MPR(b, d));
        rel[b].PB(MPR(a, d));
    }
    REP(i, s) {
        scanf("%d", &a);
        rel[0].PB(MPR(a, 0));
    }
    REP(i, t) {
        scanf("%d", &a);
        rel[a].PB(MPR(1001, 0));
    }
//    puts("OK!");
}

LL dijHeap(int s, int t) {
    dis[s] = 0ll;
    HP.insert(MPR(0ll, s));
    while (true) {
        int id = HP.begin()->SE;
//        cout << "size " << SZ(HP) << endl;
//        cout << id << ' ' << HP.begin()->FI << ' ' << dis[id] << endl;
        if (id == t) return HP.begin()->FI;
        HP.erase(HP.begin());
        REP(i, SZ(rel[id])) {
            int x = rel[id][i].FI, d = rel[id][i].SE;
            if (dis[x] > dis[id] + d) {
//                cout << x << ' ' << dis[x] << endl;
                if (dis[x] != linf) HP.erase(MPR(dis[x], x));
                HP.insert(MPR(dis[x] = dis[id] + d, x));
            }
        }
    }
}

int main() {
//    freopen("in", "r", stdin);
    int n, s, t;
    while (~scanf("%d%d%d", &n, &s, &t)) {
        input(n, s, t);
        cout << dijHeap(0, 1001) << endl;
    }
    return 0;
}

——written by Lyon