Hdu 1195 Open the Lock

来源：互联网发布：sql查询表语句怎么写编辑：程序博客网时间：2024/05/29 02:45

题目大意：有一个紧急开启密码锁的任务。密码由四位数字组成；每个数字从1到9；每次，可以对某一个数字进行加1或者减1；当从1加到9时，由9再加1会变为1；当从9减到1时，由1再减1会变为9；也可以交换两个相邻的数字，每次操作作为一个step。你的任务就是用最少的步骤解锁！

直接BFS即可

#include <cstdio>#include <iostream>#include <cstring>#include <string>#include <cstdlib>#include <algorithm>#include <cmath>#include <vector>#include <set>#include <list>#include <queue>#include <map>using namespace std;#define L(i) i<<1#define R(i) i<<1|1#define INF 0x3f3f3f3f#define pi acos(-1.0)#define eps 1e-4#define maxn 100010#define MOD 1000000007int first,last,a[4],b[4];int flag[10000];void BFS(){    queue<pair<int,int> > q;    q.push(make_pair(first,0));    flag[first]++;    while(!q.empty())    {        int x = q.front().first;        int y = q.front().second;        q.pop();        //printf("%d %d\n",x,y);        if(x == last)        {            printf("%d\n",y);            return;        }        for(int i = 3; i >= 0; i--)        {            a[i] = x % 10;            x /= 10;        }        for(int i = 0; i < 4; i++)        {            int k = 0;            a[i]++;            if(a[i] == 10)                a[i] = 1;            for(int j = 0; j < 4; j++)                k = k * 10 + a[j];            a[i]--;            if(a[i] == 0)                a[i] = 9;            if(!flag[k])            {                flag[k]++;                q.push(make_pair(k,y+1));            }            k = 0;            a[i]--;            if(a[i] == 0)                a[i] = 9;            for(int j = 0; j < 4; j++)                k = k * 10 + a[j];            a[i]++;            if(a[i] == 10)                a[i] = 1;            if(!flag[k])            {                flag[k]++;                q.push(make_pair(k,y+1));            }        }        for(int i = 0; i < 3; i++)        {            swap(a[i],a[i+1]);            int k = 0;            for(int j = 0; j < 4; j++)                k = k * 10 + a[j];            swap(a[i],a[i+1]);            if(!flag[k])            {                flag[k]++;                q.push(make_pair(k,y+1));            }        }    }}int main(){    int n,t;    scanf("%d",&t);    while(t--)    {        scanf("%d%d",&first,&last);        memset(flag,0,sizeof(flag));        BFS();    }    return 0;}

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