已知邻接矩阵，如何用dijkstra算法的matlab代码

以下是使用Dijkstra算法求解最短路径的Matlab代码：

function [dist, path] = dijkstra(adjmat, startnode, endnode)
% Dijkstra algorithm for shortest path
% Input:
%   adjmat: adjacency matrix of the graph
%   startnode: the starting node
%   endnode: the ending node
% Output:
%   dist: the shortest distance from startnode to endnode
%   path: the shortest path from startnode to endnode

n = size(adjmat, 1); % number of nodes
visited = false(1, n); % mark all nodes as unvisited
dist = inf(1, n); % initialize all distances as infinity
parent = zeros(1, n); % parent(i) is the parent node of node i in the shortest path
dist(startnode) = 0; % distance from startnode to itself is 0

while sum(visited) < n % repeat until all nodes are visited
    % find the unvisited node with the shortest distance
    mindist = inf;
    for i = 1:n
        if ~visited(i) && dist(i) < mindist
            mindist = dist(i);
            currnode = i;
        end
    end
    visited(currnode) = true; % mark current node as visited
    
    % update distances of neighbors of current node
    for i = 1:n
        if adjmat(currnode, i) > 0 % there is an edge from currnode to i
            if dist(currnode) + adjmat(currnode, i) < dist(i) % update distance if shorter
                dist(i) = dist(currnode) + adjmat(currnode, i);
                parent(i) = currnode;
            end
        end
    end
end

% construct the shortest path
path = endnode;
while path(1) ~= startnode
    path = [parent(path(1)), path];
end

end

使用方法：

假设邻接矩阵为 `adjmat`，起点为 `startnode`，终点为 `endnode`，则可以调用 `dijkstra(adjmat, startnode, endnode)` 来求得最短路径的长度 `dist` 和路径 `path`。