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?????? (BFS)

?????? (BFS) ?????????????????????????????? (DFS) ???BFS ????????????

?? (Queue)

????????? (FIFO) ?????????BFS?????C++???????????

#include 
   
    
#include 
    
     
using namespace std;
int main() {
    queue
     
       q;
    q.push(1);
    q.push(2);
    q.push(3);
    
    cout << q.front() << endl;
    q.pop();
    
    return 0;
}
     
    
   

???????

????????m?????????1?m??????n????????????1??????????????????

#include 
   
    
#include 
    
     
using namespace std;
int main() {
    int n, m;
    cin >> n >> m;
    
    queue
     
       q;
    for(int i = 1; i <= n; i++) {
        q.push(i);
    }
    
    int cur = 1;
    while(q.size() > 1) {
        int x = q.front();
        q.pop();
        if(cur != m) {
            q.push(x);
            cur++;
        } else {
            cur = 1;
        }
    }
    
    cout << q.front() << endl;
    
    return 0;
}
     
    
   

????

BFS?DFS????????????????????????BFS?????????????????????????????

???????

?????????A??B??????????????????+1?????????-1???????*2??????BFS???????A?B?

#include 
   
    
#include 
    
     
#include 
     
      
using namespace std;
bool vis[100];
int main() {
    int n, A, B, now, step;
    cin >> n >> A >> B;
    
    queue
      
       
        > q;
    q.push(make_pair(A, 0));
    vis[A] = true;
    
    while(!q.empty()) {
        now = q.front().first;
        step = q.front().second;
        q.pop();
        
        if(now == B) {
            cout << step << endl;
            break;
        }
        
        if(now + 1 <= n && !vis[now + 1]) {
            q.push(make_pair(now + 1, step + 1));
            vis[now + 1] = true;
        }
        if(now - 1 >= 0 && !vis[now - 1]) {
            q.push(make_pair(now - 1, step + 1));
            vis[now - 1] = true;
        }
        if(now * 2 <= n && !vis[now * 2]) {
            q.push(make_pair(now * 2, step + 1));
            vis[now * 2] = true;
        }
    }
    
    return 0;
}
       
      
     
    
   

???

?????????BFS???????????????????????????????????

??????

??????????BFS???????????????????????????????????

?????

????????BFS???????????????????????????????????

???????????BFS???????????????