P1228-重叠的图像

一道很水的topsort,唉？怎么交了14遍...（某人用我的代码刚好卡过，我怎么过不去...【鄙视】【鄙视】【鄙视】）

#include <bits/stdc++.h>

using namespace std;

#define INF 0x3f3f3f3f
#define MAXN 1000010
#define MAXM 5010

int n,m,len = 0,tot = 0,lin[MAXN],top = 0,a[50],vis[30],in[30];
char ch[35][35];
string st[MAXN],s1;
struct node
{
    int ix,iy;
    int ax,ay;
}q[50];
struct edge
{
    int y,next;
}e[MAXN];

inline void add(int xx,int yy)
{
    e[++tot].y = yy;
    e[tot].next = lin[xx];
    lin[xx] = tot;
}

void DFS(string xx,int le)
{    
    if(le == len + 1)
    {
        st[++top] = xx;
        return ;
    }
    for(int k = 1;k <= len;++k)
    {
        int i = a[k];
        if(vis[i] && in[i] == 0)
        {
            vis[i] = false;
            for(int j = lin[i],y;j;j = e[j].next)
                in[y = e[j].y]--;
            DFS((xx + (char)(i + 'A' - 1)),le + 1);
            vis[i] = true;
            for(int j = lin[i],y;j;j = e[j].next)
                in[y = e[j].y]++;
        }
    }
}

namespace ls {
    inline int kmax(int a, int b) { return a > b ? a : b; }
    inline int kmin(int a, int b) { return a > b ? b : a; }
}

int main()
{
    scanf("%d %d", &n, &m);
    for(int i = 1;i <= 26;++i)
    q[i].ix = INF,q[i].iy = INF;
    for(int i = 1;i <= n;++i)
    {
        for(int j = 1;j <= m;++j)
        {
            cin >> ch[i][j];
            if(ch[i][j] == '.') continue;
            int num = (int)ch[i][j] - 'A' + 1;
            if(!vis[num])
            {
                vis[num] = true;
                a[++len] = num;
            }
            q[num].ix = ls::kmin(i,q[num].ix);
            q[num].iy = ls::kmin(j,q[num].iy);
            q[num].ax = ls::kmax(i,q[num].ax);
            q[num].ay = ls::kmax(j,q[num].ay);
        }
    }
    for(int ii = 1;ii <= len;++ii)
    {
        int num = a[ii];
        char c = (char)(num + 'A' - 1);
        for(int i = q[num].ix;i <= q[num].ax;++i)
        {    
            if(ch[i][q[num].iy] != c)
            {    
                int numm = ch[i][q[num].iy] - 'A' + 1;
                in[numm]++;
                add(num,numm);
            }
            if(ch[i][q[num].ay] != c)
            {
                int numm = ch[i][q[num].ay] - 'A' + 1;
                in[numm]++;
                add(num,numm);
            }
        }
        for(int i = q[num].iy + 1;i <= q[num].ay - 1;++i)
        {    
            
            if(ch[q[num].ix][i] != c)
            {
                int numm = ch[q[num].ix][i] - 'A' + 1;
                in[numm]++;
                add(num,numm);        
            }
            if(ch[q[num].ax][i] != c)
            {
                int numm = ch[q[num].ax][i] - 'A' + 1;
                in[numm]++;
                add(num,numm);    
            }
        }
    }
    DFS(s1,1);
    sort(st + 1,st + top + 1);
    for(int i = 1;i <= top;++i)
    cout << st[i] << endl;
    return 0;
}

 以下代码会很快↓↓↓

#include <bits/stdc++.h>
#define INF ((int)(1e9))
#define LINF ((ll)(1e18))
#define pb push_back
#define mp make_pair
#define ll long long
#define _tp template
#define _tyn typename
#define ull unsigned ll
#define pii pair<int,int>
#define uint unsigned int
#define ms(_data) memset(_data,0,sizeof(_data))
#define fin(_filename) freopen(_filename,"r",stdin)
#define fout(_filename) freopen(_filename,"w",stdout)
#define msn(_data,_num) memset(_data,_num,sizeof(_data))
using namespace std;
_tp<_tyn T>void mymax( T &_a , T _b ){ if( _a < _b ) _a = _b; }
_tp<_tyn T>void mymin( T &_a , T _b ){ if( _a > _b ) _a = _b; }
int getnum(){
    char ch = '.';
    int fu = 1;
    while( ch < '0'  ||  ch > '9' ){
        ch = getchar();
        if( ch == '-' ) fu = -1;
    }
    int ret = 0;
    while( ch >= '0'  &&  ch <= '9' ){
        ret = ret * 10 + (ch-'0');
        ch = getchar();
    }
    return ret;
}
char getlet(){
    char ch = '%';
    while( ( ch < 'A'  ||  ch > 'Z' )  &&  ch != '.' ) ch = getchar();
    return ch;
}
void read( int &x, int &y ){
    x = getnum(); y = getnum();
}
void read( char &c ){
    c = getlet();
}
/////////////////////////////////////////////////////////////////////
/////////////////////////////////////////////////////////////////////
#define MAXN 40
struct Pos{
    int y,x;
    Pos(){}
    Pos( int yy , int xx ){
        y = yy;
        x = xx;
    }
};
int n,m;
int data[MAXN][MAXN];
Pos ld[MAXN],ur[MAXN];
bool exist[MAXN];

//检测一个矩形是否完整
bool test( int x ){
    for( int i = ld[x].x ; i <= ur[x].x ; i++ ){
        if( data[ld[x].y][i] != x  &&  data[ld[x].y][i] != -1 ) return 0;
        if( data[ur[x].y][i] != x  &&  data[ur[x].y][i] != -1 ) return 0;
    }
    for( int i = ur[x].y ; i <= ld[x].y ; i++ ){
        if( data[i][ld[x].x] != x  &&  data[i][ld[x].x] != -1 ) return 0;
        if( data[i][ur[x].x] != x  &&  data[i][ur[x].x] != -1 ) return 0;
    }
    return 1;
}
//消除一个矩形
void seton( int x , int a ){
    for( int i = ld[x].x ; i <= ur[x].x ; i++ ){
        data[ld[x].y][i] = a;
        data[ur[x].y][i] = a;
    }
    for( int i = ur[x].y ; i <= ld[x].y ; i++ ){
        data[i][ld[x].x] = a;
        data[i][ur[x].x] = a;
    }
}

vector<string> ans;
void dfs( string now ){
    bool gao = 0;
    for( int i = 0 ; i < 26 ; i++ ){
        if( !exist[i] ) continue;
        if( !test(i) ) continue;
        gao = 1;
        exist[i] = 0;
        int ls[MAXN][MAXN];
        memcpy(ls,data,sizeof(ls));
        seton(i,-1);
        dfs( now + (char)(i+'A') );
        memcpy(data,ls,sizeof(data));
        exist[i] = 1;
    }
    if( gao ) return;
    reverse(now.begin(),now.end());
    ans.pb(now);
}
int main(){
    //fin("frameup.in");
    //fout("frameup.out");
    for( int i = 0 ; i < 26 ; i++ ){
        ld[i].y = 0; ld[i].x = INF;
        ur[i].y = INF; ur[i].x = 0;
    }
    msn(data,-1);
    ms(exist);

    read(n,m);
    for( int i = 1 ; i <= n ; i++ ){
        for( int j = 1 ; j <= m ; j++ ){
            char c; read(c);
            if( c == '.' ) continue;
            data[i][j] = c-'A';
            exist[data[i][j]] = 1;
                       //记录矩形左下角、右上角坐标
            mymax( ld[data[i][j]].y , i );
            mymin( ld[data[i][j]].x , j );
            mymin( ur[data[i][j]].y , i );
            mymax( ur[data[i][j]].x , j );
        }
    }
    dfs("");
        //整理答案
    sort(ans.begin(),ans.end());
    for( uint i = 0 ; i < ans.size() ; i++ )
        cout << ans[i] << endl;

    return 0;
}