hdu 5012 bfs --- 慎用STL 比方MAP判重

http://acm.hdu.edu.cn/showproblem.php?pid=5012

发现一个问题 假设Sting s = '1'+'2'+'3';

s!="123"!!!!!!  而是有乱码

先贴一份自己的TLE 代码，

超时应该是由于：

1、cin

2、map判重 map find太花时间

3、string花时间

4、事实上不用两个都旋转，仅仅要旋转一个即可，这样能够省下非常多时间 包含少用了make_pair pair的判重等等....哎  二笔了  太暴力了

#include <cstdio>
#include <cstring>
#include <algorithm>
#include <iostream>
#include <set>
#include <queue>
#include <map>

using namespace std;

#define IN(s) freopen(s,"r",stdin)
#define CL(a,b) memset(a,b,sizeof(a))

map< pair<string ,string>, int>mp;

string left(string x)
{
    string tmp;
    tmp+=x[3];
    tmp+=x[2];
    tmp+=x[0];
    tmp+=x[1];
    tmp+=x[4];
    tmp+=x[5];
    //cout << "st" << tmp << endl;
    //x=tmp;
    return tmp;
}

string right(string x)
{
    string tmp;
    //tmp=x[2]+x[3]+x[1]+x[0]+x[4]+x[5];
    tmp+=x[2];
    tmp+=x[3];
    tmp+=x[1];
    tmp+=x[0];
    tmp+=x[4];
    tmp+=x[5];
    //x=tmp;
    return tmp;
}
string front(string x)
{
    string tmp;
    //tmp= x[5]+x[4]+x[2]+x[3]+x[0]+x[1];
    tmp+= x[5];
    tmp+=x[4];
    tmp+=x[2];
    tmp+=x[3];
    tmp+=x[0];
    tmp+=x[1];
    //x=tmp;
    return tmp;
}

string back(string x)
{
    string tmp;
    //tmp=x[4]+x[5]+x[2]+x[3]+x[1]+x[0];
    tmp+=x[4];
    tmp+=x[5];
    tmp+=x[2];
    tmp+=x[3];
    tmp+=x[1];
    tmp+=x[0];
    //x=tmp;
    return tmp;
}

queue< pair<string,string> >q;
string a,b;
int solve()
{
    while(!q.empty())q.pop();
    mp[ make_pair(a,b) ]=0;
    q.push( make_pair(a,b) );
    int flag=0;
    while(!q.empty())
    {
        pair <string,string> tp;
        tp.first=q.front().first;
        tp.second=q.front().second;
        if(tp.first == tp.second){flag=1; return mp[tp];}
        string tmp=left(tp.first);
        if(mp.find(make_pair(tmp,tp.second)) == mp.end()) {mp[make_pair(tmp,tp.second)]=mp[tp]+1; q.push(make_pair(tmp,tp.second)); }
        tmp=left(tp.second);if(mp.find(make_pair(tp.first,tmp))== mp.end()) { mp[make_pair(tp.first,tmp)]=mp[tp]+1;q.push(make_pair(tp.first,tmp)); }
        tmp=right(tp.first);if(mp.find(make_pair(tmp,tp.second)) == mp.end()) {mp[make_pair(tmp,tp.second)]=mp[tp]+1; q.push(make_pair(tmp,tp.second)); }
        tmp=right(tp.second);if(mp.find(make_pair(tp.first,tmp))  == mp.end()){ mp[make_pair(tp.first,tmp)]=mp[tp]+1;q.push(make_pair(tp.first,tmp)); }
        tmp=front(tp.first);if(mp.find(make_pair(tmp,tp.second)) == mp.end()) {mp[make_pair(tmp,tp.second)]=mp[tp]+1; q.push(make_pair(tmp,tp.second)); }
        tmp=front(tp.second);if(mp.find(make_pair(tp.first,tmp))  == mp.end()) { mp[make_pair(tp.first,tmp)]=mp[tp]+1;q.push(make_pair(tp.first,tmp)); }
        tmp=back(tp.first);if(mp.find(make_pair(tmp,tp.second)) == mp.end()) {mp[make_pair(tmp,tp.second)]=mp[tp]+1; q.push(make_pair(tmp,tp.second)); }
        tmp=back(tp.second);if(mp.find(make_pair(tp.first,tmp))  == mp.end()) { mp[make_pair(tp.first,tmp)]=mp[tp]+1;q.push(make_pair(tp.first,tmp)); }
        q.pop();
    }
    if(!flag)
      return -1;
}

int main()
{
    //IN("hdu5012.txt");
    while(cin>>a)
    {
        b="";//
        string tmp;
        for(int i=0;i<5;i++)
        {
            cin>>tmp;
            a+=tmp;
        }
        for(int i=0;i<6;i++)
        {
            cin>>tmp;
            b+=tmp;
        }
        printf("%d
",solve());
    }
    return 0;
}

看了别人的代码 由于这道题的技术含量不怎么高 懒得再写了。贴别人的把

用数组取代状态，至于判重 由于仅仅有六位数，所以化为整数然后判重即可了  代码来自http://blog.csdn.net/u011345461/article/details/39275009

#include <iostream>
#include <cstdio>
#include <cstring>
#include <queue>
#include <algorithm>

using namespace std;

const int MAXN = 6;

struct node{
    node() {
        memset(arr, 0, sizeof(arr));
        d = 0; 
    }
    int arr[MAXN], d;
}s, e;

int vis[MAXN * 200000];

int change(node a) {
    int num = 0;
    for (int i = 0; i < MAXN; i++) {
        num = num * 10 + a.arr[i]; 
    }
    return num;
}

bool judge(node a, node b) {
    for (int i = 0; i < MAXN; i++)
        if (a.arr[i] != b.arr[i])
            return false;
    return true;
}

node turn(node a, int i) {
    node c;
    if (i == 1) {
        c.arr[0] = a.arr[3];
        c.arr[1] = a.arr[2];
        c.arr[2] = a.arr[0];
        c.arr[3] = a.arr[1];
        c.arr[4] = a.arr[4];
        c.arr[5] = a.arr[5]; 
    }
    if (i == 2) {
        c.arr[0] = a.arr[2];
        c.arr[1] = a.arr[3];
        c.arr[2] = a.arr[1];
        c.arr[3] = a.arr[0]; 
        c.arr[4] = a.arr[4];
        c.arr[5] = a.arr[5]; 
    }
    if (i == 3) {
        c.arr[0] = a.arr[5];
        c.arr[1] = a.arr[4];
        c.arr[2] = a.arr[2];
        c.arr[3] = a.arr[3]; 
        c.arr[4] = a.arr[0];
        c.arr[5] = a.arr[1]; 
    }
    if (i == 4) {
        c.arr[0] = a.arr[4];
        c.arr[1] = a.arr[5];
        c.arr[2] = a.arr[2];
        c.arr[3] = a.arr[3]; 
        c.arr[4] = a.arr[1];
        c.arr[5] = a.arr[0];
    }
    return c;
}

int bfs() {
    memset(vis, 0, sizeof(vis));
    queue<node> q;
    q.push(s);
    node tmp; 
    vis[change(s)] = 1;
    while (!q.empty()) {
        tmp = q.front(); 
        q.pop();            
        if (judge(tmp, e)) {
            return tmp.d;
        }
        for (int i = 1; i <= 4; i++) {
            node c;
            c = turn(tmp, i);
            if (!vis[change(c)]) {
                c.d = tmp.d + 1; 
                vis[change(c)] = 1;
                q.push(c);
            } 
        }
    } 
    return -1;
}

int main() {
    while (scanf("%d", &s.arr[0]) != EOF) {
        for (int i = 1; i < MAXN; i++) 
            scanf("%d", &s.arr[i]);
        for (int i = 0; i < MAXN; i++) 
            scanf("%d", &e.arr[i]);

        printf("%d
", bfs());
    }    
    return 0;
}