改为C++语言并且手动输入权重图

在C++中实现Dijkstra算法处理手动输入权重图，我们可以先创建一个邻接表结构来存储图，并通过用户输入来填充权重。下面是一个简单的C++版本：

#include <iostream>
#include <vector>
#include <queue>
#include <climits>

// 定义图节点
struct Node {
    int id;
    std::unordered_map<int, int> neighbors; // 存储相邻节点及其权重
};

// 使用优先队列实现Dijkstra算法
void dijkstra(const std::vector<Node>& nodes, int start) {
    std::priority_queue<std::pair<int, int>, std::vector<std::pair<int, int>>, std::greater<std::pair<int, int>>> pq;
    std::vector<int> distances(nodes.size(), INT_MAX); // 初始化所有节点的距离为无穷大
    distances[start] = 0;

    pq.push({0, start});

    while (!pq.empty()) {
        int currentDistance, currentNodeId;
        tie(currentDistance, currentNodeId) = pq.top();
        pq.pop();

        if (currentDistance > distances[currentNodeId])
            continue; // 已经更新过的更优路径不会再次加入

        for (const auto& [neighborId, weight] : nodes[currentNodeId].neighbors) {
            int newDistance = currentDistance + weight;
            if (newDistance < distances[neighborId]) {
                distances[neighborId] = newDistance;
                pq.push({newDistance, neighborId});
            }
        }
    }

    for (int i = 0; i < nodes.size(); ++i) {
        if (distances[i] == INT_MAX)
            std::cout << "No path found to node " << i << std::endl;
        else
            std::cout << "Shortest distance from " << start << " to " << i << ": " << distances[i] << std::endl;
    }
}

int main() {
    std::vector<Node> nodes;
    int numNodes, numEdges, startNode;
    std::cin >> numNodes >> numEdges >> startNode; // 输入节点数、边数和起始节点

    for (int i = 0; i < numNodes; ++i) {
        nodes.push_back(Node{i});
    }

    for (int i = 0; i < numEdges; ++i) {
        int u, v, w;
        std::cin >> u >> v >> w; // 输入两个节点和它们之间的权重
        nodes[u - 1].neighbors[v - 1] = w;
        nodes[v - 1].neighbors[u - 1] = w; // 对称边
    }

    dijkstra(nodes, startNode - 1);
    return 0;
}

这个程序首先创建节点和边，然后通过循环读取用户输入来构建邻接表。注意，C++中的索引是从0开始的，所以需要减去1来对应题目描述中的1-indexed节点。