Kirill's questions

有一段代码：

read -p "Выбери число от 0 до 5: " $number
rand=$(($RANDOM%6))
if (( $(bc <<< "$rand -eq $nubmer") )); then
    echo "Не повезло"
fi

变量值不同number，rand块if仍然执行

这可能完全取决于数据类型转换，但我可能是错的

我的代码解决了这个问题

#include <bits/stdc++.h>
using namespace std;
int main() {
    int n, m;
    cin >> n >> m;

    vector <vector<int>> g(n+1, vector<int> (m+1, 0));
    vector <vector<int>> matrix(n+1, vector<int> (m+1, 0));
    queue <pair<int, int>> q;

    for(int i = 1;i <= n;i++)
        for(int j = 1;j <= m;j++)
        {
            cin >> g[i][j];
            if(g[i][j] == 1) q.push({i, j});
        }
    
    vector <int> x = {1, -1, 0, 0};
    vector <int> y = {0, 0, 1, -1};

    while(!q.empty())
    {
        auto t = q.front();
        q.pop();
        int t_x = t.first, t_y = t.second;

        for(int i = 0;i < 4;i++)
        {
            int xx = t_x + x[i], yy = t_y + y[i];
            if(xx > 0 && xx <= n && yy > 0 && yy <= m && matrix[xx][yy] == 0)
            {
                matrix[xx][yy] = matrix[t_x][t_y] + 1;
                q.push({xx, yy});
            }
        }
    }
    for(int i = 1;i <= n;i++)
    {
        for(int j = 1;j <= m;j++)
        {
            if(g[i][j] == 0)
                cout << matrix[i][j] << " ";
            else
                cout << 0 << " ";
        }   
        cout << endl;
    }
}

该解决方案在某些测试中捕获了 WA，可能是什么错误？

我的代码解决了这个问题：

为什么通过引用 DFS 传递数组会导致内存限制，但全局声明它们会通过所有测试？

错误解决方法：

#include <bits/stdc++.h>

using namespace std; 

vector <int> res;
int n, m;
void dfs(int v, vector<vector<int>> graph, vector<int> &used, vector<pair<int, int>> edges)
{
    used[v] = 1;

    for(int u:graph[v])
    {
        if(used[u] == 0)
        {
            for(int j = 1;j <= m;j++)
            {
                pair<int, int> p1 = {u, v};
                pair<int, int> p2 = {v, u};
                if(edges[j] == p1 || edges[j] == p2){
                    res.push_back(j);
                    break;
                } 
            }
            dfs(u, graph,  used, edges);
        }
    }
}
int main()
{
    int ind = 1;
    cin >> n >> m;
    vector <vector<int>> graph(n+1);
    vector <int> used(n+1, 0);
    vector <pair<int, int>> edges(m+1);

    for(int i = 0;i < m;i++)
    {
        int t1, t2;
        cin >> t1 >> t2;
        graph[t1].push_back(t2);
        graph[t2].push_back(t1);
        edges[ind] = {t1, t2};
        ind++;
    }
    dfs(1, graph,  used, edges);
    
    cout << res.size() << endl;
    for(int x:res) cout << x << " ";

}