HDU 1548 A strange lift

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <cmath>
#include <queue>
#define sc(x) scanf("%d",&(x))
#define pf(x) printf("%d
", x)
#define CL(x, y) memset(x,y,sizeof(x))
using namespace std;
const int MAX = 205;
int N, a, b, i, j, temp;
int used[MAX], lift[MAX];
void BFS(int x, int y);
struct node
{
    int num;
    int step;
};
queue <node> Q;
int main()
{
    while(cin >> N, N)
    {
        cin >> a >> b;
        CL(lift, 0);//这个地方要清空，WA了几次，留作纪念
        CL(used, 0);
        for(i = 1; i <= N; i++)
            sc(lift[i]);
        BFS(a, b);
    }
    return 0;
}
void BFS(int front, int rear)
{
    while(!Q.empty())
        Q.pop();//Q.clear();清空
    node first, cur, next;
    first.num = front;
    first.step = 0;
    used[front] = 1;
    Q.push(first);
    while(!Q.empty())
    {
        cur = Q.front();
        Q.pop();
        if(cur.num == rear)
        {
            cout << cur.step << endl;
            return ;
        }
        for(j = 0; j < 2; j++)
        {
            temp = j==0 ? (cur.num+lift[cur.num]) : (cur.num-lift[cur.num]);
            //            cout << temp << endl;
            if(!used[temp] && temp<=N && temp>=1)
            {
                next.num = temp;
                next.step = cur.step+1;
                used[temp] = 1;
//                cout << next.num << " " << next.step << endl;
                Q.push(next);
                Q.push(next);
            }
        }
    }
    pf(-1);
    return ;
}

这题目跟Prime Path相似，原来使用结构体队列跟一个数组、一个队列效果一样，但是觉得CL（），特别重要，还是需要手工debug的

才明白差距是在不断练习中发现的