Tour Route 哈密顿回路

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题目

http://acm.hdu.edu.cn/showproblem.php?pid=3414

代码

#include <iostream>
#include <cstdio>
#include <cstring>
using namespace std;
const int maxn=1e3;
inline int read()
{
	int f=1,num=0;
	char ch=getchar();
	while (!isdigit(ch)) { if (ch=='-') f=-1; ch=getchar();	}
	while (isdigit(ch)) num=(num<<1)+(num<<3)+(ch^48), ch=getchar();
	return num*f;
}
int n,Next[maxn+3],a[maxn+3][maxn+3];
bool eprepend(int s)
{
    memset(Next,-1,sizeof(Next));
    int head=s, tail=s;
    for (int i=0;i<n;++i)
    {
        if (i==s) continue;
        if (a[i][head])//直接插入
        {
            Next[i]=head;
            head=i;
        }
        else//找到合适的位置插入
        {
            int pre=head,pos=Next[head];
            while (pos!=-1 && a[pos][i])
            {
                pre=pos;
                pos=Next[pos];
            }
            Next[pre]=i;
            Next[i]=pos;
            if (pos==-1)
                tail=i;
        }
    }
    if (a[tail][head])
    {
        Next[tail]=head;
        return true;
    }
    return false;
}
bool Hamilton()
{
    for (int i=0;i<n;++i)
        if (eprepend(i))
            return true;
    return false;
}
int main()
{
    while (~(n=read()),n)
    {
        for (int i=0;i<n;++i)
            for (int j=0;j<n;++j)
                a[i][j]=read();
        if (n==1)
            puts("1");
        else if (n==2 || !Hamilton())
            puts("-1");
        else
        {
        	for (int i=0,j=0;i<n;++i,j=Next[j])
                printf("%d%c",j+1,i==n-1?'\n':' ');
		}
    }
    return 0;
}