C++中的迭代深化搜索

Iterative Deepening Search in C++

本文关键字：搜索 迭代 C++      更新时间：2023-10-16

好吧，首先，我不知道迭代深化在做什么。我一直在努力让这段代码发挥作用，但我做不到。我在网上查了一下，在C++中找不到任何关于这次搜索的参考资料。

void Graph::IDS(int x, int required, int depth = 1)
{
    if(x == required) return;
    cout << "Iterated Deepening Search for " << required << ", starting from vertex " << x << " : " << endl;
    IDS_util(x, required, depth);
    cout << endl;
}
void Graph::IDS_util(int x, int required, int depth)
{
    stack s;
    bool *visited = new bool[n+1];
    int i, j, k;
    for(i = 0; i <= n; i++)
        visited[i] = false;
    cout << "Depth = " << depth << ":  ";
    visited[x] = true;
for (int c = 1; c <= n; c++){
    s.push(x);
    if(isConnected(x, c) && !visited[c])
    {
        for (j = 0; j < depth; j++){
            k = s.pop();
            if(k == required) return;
            cout << "[" << k <<"] ";
            for (i = n; i >= 0 ; --i)
                if (isConnected(k, i) && !visited[i]) {
                    s.push(i);
                    visited[i] = true;
                }
        }
    }
}
    if(depth == n)  return;
    cout << endl;
    IDS_util(x, required, depth+1);
}

邻接矩阵的输出：

0,1,1,1,0,0,0,0,0
0,0,0,0,1,0,0,0,0
0,0,0,0,0,1,1,0,0
0,0,0,0,0,0,0,1,0
0,0,0,0,0,0,0,0,1
0,0,0,0,0,0,0,0,0
0,0,0,0,0,0,0,0,0
0,0,0,0,0,0,0,0,0
0,0,0,0,0,0,0,0,0

这是该图的定向版本：

         [1] 
       /  |  
    [2]  [3]  [4]
    /    /      
  [5]  [6] [7]   [8]
  / 
[9]

是：

Iterated Deepening Search for 7, starting from vertex 1 : 
Depth = 0:  
Depth = 1:  [1] 
Depth = 2:  [1] [2] 
Depth = 3:  [1] [2] [5] 
Depth = 4:  [1] [2] [5] [9] 
Depth = 5:  [1] [2] [5] [9] [3] 
Depth = 6:  [1] [2] [5] [9] [3] [6] 
Depth = 7:  [1] [2] [5] [9] [3] [6]

从理论上讲，我知道搜索应该做什么，我可以在一定程度上判断我的搜索在做什么，但我不知道如何解决它。任何人能提供的任何帮助都将不胜感激。

我几乎可以肯定这不是最有效的方法，但我找到了一种有效的方法。

void Graph::IDS(int x, int required)
{
    if(x == required) return;
    cout << "Iterated Deepening Search for " << required << ", starting from vertex " << x << " : " << endl;
    for (int d = 0  ; d <= n ; d++)
        if (IDS_util(x, required, d))
            return;
    cout << required << " was unable to be located via " << x << endl;
}

bool Graph::IDS_util(int x, int required, int depth){
    if(x == required) return true;
    stack s, x_child;
    bool *visited = new bool[n+1];
    int i,k, d, sub_k;
    for(i = 0; i <= n; i++) visited[i] = false;
    visited[x] = true;
    for (i = n; i >= 0 ; --i)
        if (isConnected(x, i))
            x_child.push(i);
    cout << '[' << x << "] ";
    while(!x_child.isEmpty()){
        k = x_child.pop();
        s.push(k);
        for(d = 0; d < depth; d++){
            sub_k = s.pop();
            if(sub_k == required)  return true;
            cout << '[' << sub_k << "] ";
            for (i = 0; i <= n; i++){
                if (isConnected(sub_k, i) && !visited[i]) {
                    if (i == required){
                        cout << "nn" << required << " is a child of " << sub_k << endl;
                        return true;
                    }
                    s.push(i);
                    visited[i] = true;
                }
            }
        }
    }
    cout<<endl;
    delete [] visited;
    return false;
}
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