OJ-Problems-Source/HDOJ/1530_autoAC.cpp

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#include<iostream>
#include<stdio.h>
#include<string.h>
using namespace std;
#define NMAX 55
bool path[NMAX][NMAX];
int n,mmax;
int dp[NMAX];
bool v[NMAX];
int seq[NMAX], seq_pos;
bool dfs(int pos, int size)
{
int i, j, unvis;
bool tv[NMAX];
unvis = 0;
for (i=pos; i<n; i++)
{
if (!v[i])
{
unvis ++;
}
}
if (unvis == 0)
{
if (size > mmax)
{
mmax = size;
seq_pos = 0;
seq[ seq_pos ++] = pos+1;
return true;
}
return false;
}
for (i=pos; i < n && unvis > 0 ; i++)
{
if (!v[i])
{
if (unvis + size <= mmax || dp[i] + size <= mmax)
{
return false;
}
v[i] = true;
unvis --;
memcpy(tv, v, sizeof(v));
for (j=0; j<n; j++) //U N(vi);
{
if (!path[i][j])
{
v[j] = true;
}
}
if ( dfs(i, size+1) )
{
seq[ seq_pos ++] = pos+1;
return true;
}
memcpy(v, tv, sizeof(v));
}
}
return false;
}
int max_clique()
{
int i,j;
mmax = 0;
for (i=0; i<n; i++)
{
path[i][i] = false;
}
for (i=n-1; i>=0; i--)
{
for (j=0; j<n; j++)
{
v[j] = !path[i][j];
}
dfs(i, 1);
dp[i] = mmax;
}
return mmax;
}
int main()
{
while(scanf("%d",&n))
{
if(n==0)
break;
for(int i=0; i<n; i++)
{
for(int j=0; j<n; j++)
{
scanf("%d",&path[i][j]);
}
}
printf("%d\n",max_clique());
}
return 0;
}