|BZOJ 2763|最短路|[JLOI2011]飞行路线

BZOJ 2763

分层图最短路

注意：priority_queue默认排序序列是从大到小的，所以重载小于符号时要a>b
以后权值一律写w，不要用v或c！

#include<cstdio>#include<cstring>#include<algorithm>#include<vector>#include<queue>#define fo(i, j, k) for (i=(j);i<=(k);i++)#define fd(i, k, j) for (i=(k);i>=(j);i--)#define fg(i, u) for (i=0;i<G[u].size();i++)#define fe(i, u) for (i=head[u];i!=-1;i=e[i].next)#define rd(a) scanf("%d", &a)#define rd2(a, b) scanf("%d%d", &a, &b)#define rd3(a, b, c) scanf("%d%d%d", &a, &b, &c)#define ms(i, j) memset(i, j, sizeof i)#define FN2 "bzoj2763" using namespace std;const int MAXN = 1200100, INF = 0x3f3f3f3f;struct edge{int v, c;}e[MAXN<<2];struct data {    int u, c;    bool operator < (data const &b) const {        return c>b.c;    }};int n, m, k, en, dis[MAXN], s, t, vi[MAXN];vector<int> G[MAXN];void ins(int u, int v, int c) {    en++, e[en].v = v, e[en].c = c, G[u].push_back(en);}void pre() {    int i; en = 0;    fo (i, 0, n*(k+2)) G[i].clear(), dis[i] = INF, vi[i] = false;}void init() {    int i,j;    pre();    rd2(s, t);    fo (i, 1, m) {        int a, b, c;        rd3(a, b, c);        fo (j, 0, k) {            ins(a+j*n, b+j*n, c), ins(b+j*n, a+j*n, c);            if (j!=k) ins(a+j*n, b+(j+1)*n, 0), ins(b+j*n, a+(j+1)*n, 0);        }    }}void solve() {    int i, ans = INF;    priority_queue<data> q;    dis[s] = 0, q.push((data){s, dis[s]});    while (!q.empty()) {        data p = q.top(); q.pop();        int u = p.u;        if (vi[u]) continue;        vi[u] = true;        for (i=0;i<G[u].size();i++) {            int v = e[G[u][i]].v;            if (dis[v]>dis[u]+e[G[u][i]].c) {                dis[v] = dis[u]+e[G[u][i]].c;//用dis[u]，因为有重边                 q.push((data){v, dis[v]});            }        }    }    fo (i, 0, k) {        ans = min(ans, dis[t+i*n]);    }    printf("%d\n", ans);}int main() {    #ifndef ONLINE_JUDGE    freopen(FN2".in","r",stdin);freopen("1.out","w",stdout);    #endif    while (rd3(n,m,k)==3) init(), solve();    return 0;}