codevs2292 图灵机游戏

来源：互联网发布：传智播客2017java 编辑：程序博客网时间：2024/06/07 13:27

#include<cstdio>#include<iostream>#include<cstring>#include<cstdlib>#include<algorithm>#include<string>#include<vector>#include<map>#include<set>#include<queue>#define R0(i,n) for(int i=0;i<n;++i)#define R1(i,n) for(int i=1;i<=n;++i)#define CLR(x,c) memset(x,c,sizeof x)using namespace std;int read(){    int x=0,f=1;char ch=getchar();    while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}    while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}    return x*f;}int a[100001],ci[100001],n;bool use[100001];void bfs(){queue<int>q;    int i;    q.push(a[1]);    ci[a[1]]=1;    use[a[1]]=true;    while (!q.empty()){    int t=q.front();q.pop();        if (t==n) break;        if (!use[a[t]]){            q.push(a[t]);            ci[a[t]]=ci[t]+1;            use[a[t]]=1;        }        if (t<n&&!use[t+1]){            q.push(t+1);            ci[t+1]=ci[t]+1;            use[t+1]=1;        }        if (t>1&&!use[t-1]){            q.push(t-1);            ci[t-1]=ci[t]+1;            use[t-1]=1;        }            }}int main(){    n=read();    R1(i,n)a[i]=read();    bfs();    if (n==1) printf("0\n");    else printf("%d\n",ci[n]);}

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