HDU-2017 多校训练赛9-1006-Senior Pan

来源：互联网发布：如何关闭mac更新系统编辑：程序博客网时间：2024/06/06 21:59

ACM模版

描述

题解

官方题解：

比赛时知道是最短路，但是没有写出来，真无奈ㄟ( ▔, ▔ )ㄏ……

代码

#include <queue>#include <cstdio>#include <cstring>#include <iostream>#include <algorithm>using namespace std;typedef long long ll;const ll INF = 0x3f3f3f3f3f3f3f3f;const int MAXN = 1e5 + 10;const int MAGIC = 20;struct Edge{    int v, val, net;} edg[MAXN];struct node{    int x;    ll step;};int n, m, k, tot;int hed[MAXN];int a[MAXN];int vis[MAXN];ll dis[MAXN];priority_queue<node> pqn;bool operator < (node a, node b){    return a.step > b.step;}void addedge(int u, int v, int val){    edg[tot].v = v;    edg[tot].val = val;    edg[tot].net = hed[u];    hed[u] = tot++;}ll dijkstra(){    while (!pqn.empty())    {        node now = pqn.top();        pqn.pop();        if (vis[now.x])        {            return now.step;        }        for (int i = hed[now.x]; ~i; i = edg[i].net)        {            int next = edg[i].v;            if (dis[next] > now.step + edg[i].val)            {                dis[next] = now.step + edg[i].val;                pqn.push(node{next, dis[next]});            }        }    }    return INF;}void init(){    memset(dis, 0x3f, sizeof(dis));    memset(vis, 0, sizeof(vis));    while (!pqn.empty())    {        pqn.pop();    }}ll solve(int k){    ll ans = INF;    for (int i = 0; i < MAGIC; i++)    {        init();        for (int j = 0; j < k; j++)        {            if (a[j] & (1 << i))            {                pqn.push(node{a[j], 0});                dis[a[j]] = 0;            }            else            {                vis[a[j]] = 1;            }        }        ans = min(ans, dijkstra());        init();        for (int j = 0; j < k; j++)        {            if (a[j] & (1 << i))            {                vis[a[j]] = 1;            }            else            {                pqn.push(node{a[j], 0});                dis[a[j]] = 0;            }        }        ans = min(ans, dijkstra());    }    return ans;}int main(){    int T;    scanf("%d", &T);    for (int ce = 1; ce <= T; ce++)    {        tot = 0;        memset(hed, -1, sizeof(hed));        scanf("%d%d", &n, &m);        int u, v, w;        while (m--)        {            scanf("%d%d%d", &u, &v, &w);            addedge(u, v, w);        }        scanf("%d", &k);        for (int i = 0; i < k; i++)        {            scanf("%d", &a[i]);        }        printf("Case #%d: %lld\n", ce, solve(k));    }    return 0;}

阅读全文

0 0