hdu2544（自己实现优先队列）

hdu2544  dij水题，用来测试自己实现优先队列对不对

  1 #include <stdio.h>
  2 #include <string.h>
  3 #include <stdlib.h>
  4 #include <algorithm>
  5 #include <iostream>
  6 #include <queue>
  7 #include <stack>
  8 #include <vector>
  9 #include <map>
 10 #include <set>
 11 #include <string>
 12 #include <math.h>
 13 using namespace std;
 14 #pragma warning(disable:4996)
 15 typedef long long LL;
 16 const int INF = 1 << 30;
 17 const int N = 1000 + 10;
 18 int len;
 19 struct node
 20 {
 21     int v, cost;
 22     int next;
 23 }g[10000+10];
 24 int head[N], e;
 25 int dist[N];
 26 bool vis[N];
 27 void init(int n)
 28 {
 29     for (int i = 1; i <= n; ++i)
 30         head[i] = -1;
 31     e = 0;
 32 }
 33 void addEdge(int u, int v, int c)
 34 {
 35     g[e].v = v;
 36     g[e].cost = c;
 37     g[e].next = head[u];
 38     head[u] = e++;
 39 }
 40 struct node2
 41 {
 42     int v, dist;
 43     bool operator<(const node2&rhs)const
 44     {
 45         return dist > rhs.dist;
 46     }
 47 }q[100000];
 48 
 49 
 50 void push(node2 tmp)//在队尾加入一个元素，只要调整到父亲结点不大于自己即可
 51 {
 52     int adjustIndex = ++len;
 53     for (int i = adjustIndex / 2; i >= 1; i /= 2)
 54     {
 55         if (q[i].dist < tmp.dist)
 56             break;
 57         q[adjustIndex] = q[i];
 58         adjustIndex = i;
 59     }
 60     q[adjustIndex] = tmp;
 61 }
 62 
 63 node2 get()
 64 {
 65     node2 ret = q[1];//得到队首元素
 66     node2 tmp = q[len--];//将队尾元素放到队首
 67     int adjustIndex = 1;
 68     //调整成一个小顶堆
 69     for (int i = adjustIndex * 2; i <= len; i = i * 2)
 70     {
 71         if (i < len && q[i].dist > q[i + 1].dist)
 72             i++;
 73         if (tmp.dist < q[i].dist)
 74             break;
 75         q[adjustIndex] = q[i];
 76         adjustIndex = i;
 77     }
 78     q[adjustIndex] = tmp;
 79     return ret;
 80 }
 81 
 82 void dij(int n)
 83 {
 84     //priority_queue<node2> q;
 85     for (int i = 1; i <= n; ++i)
 86     {
 87         dist[i] = INF;
 88         vis[i] = false;
 89     }
 90     len = 0;
 91     dist[1] = 0;
 92     node2 cur, tmp;
 93     cur.v = 1;
 94     cur.dist = 0;
 95     //q.push(cur);
 96     push(cur);
 97     while (len!=0)
 98     {
 99         cur = get();
100         //cur = q.top();
101         //q.pop();
102         int x = cur.v;
103         if (vis[x]) continue;
104         vis[x] = true;
105         for (int i = head[x]; i != -1; i = g[i].next)
106         {
107             int v = g[i].v;
108             tmp.v = v;
109             if (dist[v] > dist[x] + g[i].cost)
110             {
111                 tmp.dist = dist[v] = dist[x] + g[i].cost;
112                 //q.push(tmp);
113                 push(tmp);
114             }
115         }
116 
117     }
118 }
119 int main()
120 {
121     int n, m, a, b, c, i;
122     while (scanf("%d%d", &n, &m) ,n)
123     {
124         init(n);
125         for (i = 0; i < m; ++i)
126         {
127             scanf("%d%d%d", &a, &b, &c);
128             addEdge(a, b, c);
129             addEdge(b, a, c);
130         }
131         dij(n);
132         printf("%d\n", dist[n]);
133     }
134 }
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posted @ 2015-04-26 19:24  justPassBy  阅读(205)  评论(0)  编辑  收藏  举报