从小事看国人和外国人的素质差异

/* THE PROGRAM IS MADE BY PYY */
/*----------------------------------------------------------------------------//
Copyright (c) 2012 panyanyany All rights reserved.

URL   : http://acm.hdu.edu.cn/showproblem.php?pid=1548 Name  : 1548 A strange lift

Date  : Sunday，April 1, 2012
Time Stage : many hours

Result:
5685230	2012-04-01 18:17:43	Accepted	1548
0MS	244K	1689 B
C++	pyy

Test Data :

Review :
一开始一直MLE，真是莫名奇妙啊，完全不知道原因，在原代码的基础上改来改去不得其法。
后来直接重新写一遍，酸酸地AC了……
//----------------------------------------------------------------------------*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <vector>

#include <algorithm>
#include <iostream>
#include <queue>

using namespace std ;

#define MEM(a, v)        memset (a, v, sizeof (a))    // a for address, v for value
#define max(x, y)        ((x) > (y) ? (x) : (y))
#define min(x, y)        ((x) < (y) ? (x) : (y))

#define INF        (0x3f3f3f3f)
#define MAXN    (202)
#define MAXM    (100)

#define DB    /##/
#define LL __int64

#define _IN(a)			(0 < (a) && (a) <= n)
#define CHECK(a)		(_IN(a) && -1 == step[(a)])
#define LOAD(a)			do { q.push(a); step[(a)] = step[t] + 1; } while(0)

int		n, a, b;
int		step[MAXN], next[MAXN];

void bfs()
{
int t, na, nb;
queue<int>	q;

q.push(a);
while (!q.empty())
{
t = q.front();
q.pop();

if (t == b)
break;

na = t + next[t];
nb = t - next[t];
if (CHECK(na))
{
LOAD(na);
/*
q.push(na);
step[na] = step[t] + 1;
*/
}
if (CHECK(nb))
{
LOAD(nb);
/*
q.push(nb);
step[nb] = step[t] + 1;
*/
}
}
}

int main()
{
int i;
while (scanf("%d", &n), n)
{
scanf("%d %d", &a, &b);
MEM(step, -1);
step[a] = 0;
for (i = 1; i <= n; ++i)
scanf("%d", &next[i]);
bfs();
printf ("%d\n", step[b]);
}
return 0;
}