【POJ 1084】 Square Destroyer

【题目链接】

http://poj.org/problem?id=1084

【算法】

迭代加深

【代码】

#include <algorithm>
#include <bitset>
#include <cctype>
#include <cerrno>
#include <clocale>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <deque>
#include <exception>
#include <fstream>
#include <functional>
#include <limits>
#include <list>
#include <map>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <utility>
#include <vector>
#include <cwchar>
#include <cwctype>
#include <stack>
#include <limits.h>
using namespace std;

int i,n,T,step,k,x;
bool dest[];

inline bool is_square(int x,int y,int len)
{
        int i,l,r;
        bool ret = true;
        l = (x - ) * ( * n + ) + y;
        r = l + len - ;
        for (i = l; i <= r; i++) ret &= (dest[i] ^ );
        l = (x + len - ) * ( * n + ) + y;
        r = l + len - ;
        for (i = l; i <= r; i++) ret &= (dest[i] ^ );
        l = n * x + (x - ) * (n + ) + y;
        r = n * (x + len - ) + (x + len - ) * (n + ) + y;
        for (i = l; i <= r; i +=  * n + ) ret &= (dest[i] ^ );
        l = n * x + (x - ) * (n + ) + y + len;
        r = n * (x + len - ) + (x + len - ) * (n + ) + y + len;
        for (i = l; i <= r; i +=  * n + ) ret &= (dest[i] ^ );
        return ret;
}
inline bool check()
{
        int i,j,k;
        for (k = ; k <= n; k++)
        {
                for (i = ; i <= n - k + ; i++)
                {
                        for (j = ; j <= n - k + ; j++)
                        {
                                if (is_square(i,j,k))
                                        return false;
                        }
                }
        }
        return true;
}
inline bool IDDFS(int dep)
{
        int i,j,k,x,y,len,l,r;
        if (dep > step)
        {
                if (check())
                        return true;
                else return false;
        }
        x = y = len = ;
      for (k = ; k <= n; k++)
        {
                for (i = ; i <= n - k + ; i++)
                {
                        for (j = ; j <= n - k + ; j++)
                        {
                                if (is_square(i,j,k))
                                {
                                        x = i;
                                         y = j;
                                        len = k;
                                        break;
                                }
                        }
                        if (x) break;
                }
                if (x) break;
        }
        l = (x - ) * ( * n + ) + y;
        r = l + len - ;
        for (i = l; i <= r; i++)
        {
                dest[i] = true;
                if (IDDFS(dep+))
                        return true;
                dest[i] = false;
        }
        l = (x + len - ) * ( * n + ) + y;
        r = l + len - ;
        for (i = l; i <= r; i++)
        {
                dest[i] = true;
                if (IDDFS(dep+))
                        return true;
                dest[i] = false;
        }
        l = n * x + (x - ) * (n + ) + y;
        r = n * (x + len - ) + (x + len - ) * (n + ) + y;
        for (i = l; i <= r; i +=  * n + )
        {
                dest[i] = true;
                if (IDDFS(dep+))
                        return true;
                dest[i] = false;
        }
        l = n * x + (x - ) * (n + ) + y + len;
        r = n * (x + len - ) + (x + len - ) * (n + ) + y + len;
        for (i = l; i <= r; i +=  * n + )
        {
                dest[i] = true;
                if (IDDFS(dep+))
                        return true;
                dest[i] = false;
        }
        return false;
}

int main()
{

        scanf("%d",&T);
        while (T--)
        {
                scanf("%d",&n);
                for (i = ; i <=  * n * (n + ); i++) dest[i] = false;
                scanf("%d",&k);
                for (i = ; i <= k; i++)
                {
                        scanf("%d",&x);
                        dest[x] = true;
                }
                for (i = ; i <=  * n * (n + ); i++)
                {
                        step = i;
                        if (IDDFS())
                                break;
                }
                printf("%d\n",step);
        }

        return ;

}