单元最短路径算法代码c

单元最短路径算法（Dijkstra算法）是一种用于计算图中最短路径的算法。下面是用C语言编写的Dijkstra算法代码示例：

#include <stdio.h>
#define INF 99999

void dijkstra(int graph[ ][ ], int n, int start) {
   int cost[n][n], distance[n], pred[n];
   int visited[n], count, mindistance, nextnode, i, j;
   
   // 初始化
   for(i = 0; i < n; i++) {
      for(j = 0; j < n; j++) {
         if(graph[i][j] == 0)
            cost[i][j] = INF;
         else
            cost[i][j] = graph[i][j];
      }
   }
   
   for(i = 0; i < n; i++) {
      distance[i] = cost[start][i];
      pred[i] = start;
      visited[i] = 0;
   }
   
   distance[start] = 0;
   visited[start] = 1;
   count = 1;
   
   while(count < n - 1) {
      mindistance = INF;
      
      // 找到下一个最短距离的节点
      for(i = 0; i < n; i++) {
         if(distance[i] < mindistance && !visited[i]) {
            mindistance = distance[i];
            nextnode = i;
         }
      }
      
      visited[nextnode] = 1;
      
      // 更新距离数组
      for(i = 0; i < n; i++) {
         if(!visited[i]) {
            if(mindistance + cost[nextnode][i] < distance[i]) {
               distance[i] = mindistance + cost[nextnode][i];
               pred[i] = nextnode;
            }
         }
      }
      count++;
   }
   
   // 输出最短路径和距离
   for(i = 0; i < n; i++) {
      if(i != start) {
         printf("\n距离节点 %d 的最短路径 = %d", i, distance[i]);
         printf("\n最短路径 = %d", i);
         
         j = i;
         do {
            j = pred[j];
            printf("<-%d", j);
         }while(j != start);
      }
   }
}

int main() {
   int graph[5][5] = {{0, 10, 0, 30, 100},
                      {10, 0, 50, 0, 0},
                      {0, 50, 0, 20, 10},
                      {30, 0, 20, 0, 60},
                      {100, 0, 10, 60, 0}};
   int n = 5, start = 0;
   dijkstra(graph, n, start);
   return 0;
}

这个代码示例中包括了Dijkstra算法的实现，主要是通过使用邻接矩阵来表示图，并利用循环来更新最短路径和距离数组。最后输出了每个节点到起点的最短路径及其距离。