UVa 12661 Funny Car Racing (dijkstra)

题意：给定一个有向图，每条路有5个整数修饰，u, v, a, b, t,表示起点为u，终点为v，打开时间a，关闭时间为b，通过时间为t，打开关闭是交替进行的，

问你从s到t最短时间是多少。

析：使用dijkstra算法，从每个结点出发，求最短路，并维护时间的最小值，这个可以用优先队列，然后考虑能不能通过这条路，如果t<a，可以在输入时处理。

代码如下：

#pragma comment(linker, "/STACK:1024000000,1024000000")

#include <cstdio>

#include <string>

#include <cstdlib>

#include <cmath>

#include <iostream>

#include <cstring>

#include <set>

#include <queue>

#include <algorithm>

#include <vector>

#include <map>

#include <cctype>

#include <cmath>

#include <stack>

#include <sstream>

#define debug() puts("++++")

#define gcd(a, b) __gcd(a, b)

#define lson l,m,rt<<1

#define rson m+1,r,rt<<1|1

#define freopenr freopen("in.txt", "r", stdin)

#define freopenw freopen("out.txt", "w", stdout)

using namespace std;

typedef long long LL;

typedef unsigned long long ULL;

typedef pair<int, int> P;

const int INF = 0x3f3f3f3f;

const double inf = 0x3f3f3f3f3f3f;

const double PI = acos(-1.0);

const double eps = 1e-5;

const int maxn = 300 + 10;

const int mod = 1e6;

const int dr[] = {-1, 0, 1, 0};

const int dc[] = {0, 1, 0, -1};

const char *de[] = {"0000", "0001", "0010", "0011", "0100", "0101", "0110", "0111", "1000", "1001", "1010", "1011", "1100", "1101", "1110", "1111"};

int n, m;

const int mon[] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

const int monn[] = {0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

inline bool is_in(int r, int c){

  return r >= 0 && r < n && c >= 0 && c < m;

}

struct Node{

  int to, a, b, t;

};

vector<Node> G[maxn];

int d[maxn];

int dijkstra(int s, int ttt){

  priority_queue<P, vector<P>, greater<P> > pq;

  pq.push(P(0, s));

  fill(d, d+n+1, INF);

  d[s] = 0;

  while(!pq.empty()){

    P p = pq.top();  pq.pop();

    if(p.second == ttt)  return p.first;

    int v = p.second;

    if(d[v] < p.first)  continue;

    for(int i = 0; i < G[v].size(); ++i){

      Node &u = G[v][i];

      int t =  p.first % (u.a+u.b);

      if(t + u.t <= u.a && d[u.to] > d[v] + u.t){

        d[u.to] = d[v] + u.t;

        pq.push(P(d[u.to], u.to));

      }

      else if(t + u.t > u.a){

        int tt = u.a + u.b - t + u.t;

        if(d[u.to] > d[v] + tt){

          d[u.to] = d[v] + tt;

          pq.push(P(d[u.to], u.to));

        }

      }

    }

  }

  return 0;

}

int main(){

  int kase = 0;

  int s, t;

  while(scanf("%d %d %d %d", &n, &m, &s, &t) == 4){

    int u, v, a, b, tt;

    for(int i = 1; i <= n; ++i)  G[i].clear();

    while(m--){

      scanf("%d %d %d %d %d", &u, &v, &a, &b, &tt);

      if(tt > a)  continue;

      G[u].push_back((Node){v, a, b, tt});

    }

    printf("Case %d: %d\n", ++kase, dijkstra(s, t));

  }

  return 0;

}

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UVa 12661 Funny Car Racing (dijkstra)

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