uva_658 It's not a Bug, it's a Feature! Dijkstra(优先队列)

来源：互联网发布：新东方考研单词软件编辑：程序博客网时间：2024/06/03 01:40
#include <cstdio>#include <algorithm>#include <queue> using namespace std;#define N 21#define M 101 const int inf = 500000000; int pre[2][M], next[2][M]; int t[M];int d[1<<N]; typedef pair<int, int> pii; void dijkstra(int n, int m){       for (int i = 0; i < (1 << n); i++)d[i] = inf;       priority_queue<pii, vector<pii>, greater<pii> > q;        d[(1 << n) - 1] = 0;        q.push(make_pair(0, (1 << n) - 1));       while (!q.empty())       {              pii u = q.top();q.pop();              int x = u.second;              if (u.first != d[x])continue;              for (int i = 0; i < m ; i++)if (((x | pre[0][i]) == x) && (x&pre[1][i])== x)              {                     int v = x | next[0][i];                     v &= next[1][i];                     if (d[x] + t[i] < d[v])                      {                               d[v] = d[x] + t[i];                               q.push(make_pair(d[v], v));                     }               }       } }        int ca = 1; int main(){      int n, m;      char b1[N], b2[N];      while (scanf("%d %d", &n, &m) != EOF && (m + n))      {            for (int i = 0; i < m; i++)            {                   scanf("%d %s %s", t + i, b1, b2);                   pre[0][i] = pre[1][i] = next[0][i] = next[1][i] = 0;                   for (int j = 0; j < n; j++)                   {                         if (b1[j] == '+')pre[0][i] |= (1 << j);                         if (b1[j] != '-')pre[1][i] |= (1 << j);                         if (b2[j] == '+')next[0][i] |= (1 << j);                         if (b2[j] != '-')next[1][i] |= (1 << j);                   }            }            dijkstra(n, m);            printf("Product %d\n", ca++);             if (d[0] == inf)puts("Bugs cannot be fixed.");            else printf("Fastest sequence takes %d seconds.\n", d[0]);            puts("");       }      return 0;}