SGU 122 The book（哈密顿回路）

#include <cstdio>  
#include <cstdlib>  
#include <cstring>  
#include <string>  
#include <iostream>  
using namespace std;  
const int mn =1100;  
int n,k,i,j,listNum;  
int L[mn],R[mn],head,tail;  
bool adj[mn][mn] ={0};  
bool visit[mn];  
string s;  
void reverse(){//checked  
    int tmp[mn],t = head,num=1;  
    tmp[num]=head;  
    while (t!=tail){  
    t=R[t];tmp[++num]=t;  
    }tmp[++num]=tail;  
    if (adj[head][tail]){  
    R[tail] = head;L[head] = tail;  
    return ;  
    }  
    else for (int i=2;i<num-1;++i)  
         if (adj[head][tmp[i+1]] && adj[tail][tmp[i]]){  
         L[head] = R[head];R[head] = tmp[i+1];  
         L[tmp[i+1]] = head;R[tail] = tmp[i];  
         R[tmp[i]]=L[tmp[i]];L[tmp[i]] = tail;  
         for (int j = i-1;j>=2;--j){  
             int p = L[tmp[ j ]];  
             L[tmp[ j ]] = R[tmp[ j ]];R[tmp[ j ]]=p;  
         }  
         return;  
         }  
}  
void add(){  
    int tmp[mn],t = head,num=1;  
    tmp[num]=head;  
    while (t!=tail){  
    t=R[t];tmp[++num]=t;  
    }tmp[++num]=tail;int pos;  
    for (int i=1;i<=n;++i)  
    if (visit[i]){pos = i;visit[i]=false;break;}  
    for (int i =1;i<=num;++i)  
    if (adj[tmp[i]][pos]){  
        head = R[tmp[i]];tail = pos;  
        R[tmp[i]] = pos;  
        L[pos] = tmp[i];  
        R[pos] = 0;  
        listNum++;  
        return;  
    }  
}  
int findHead(){//checked  
    for (int i=1;i<=n;++i)  
    if (visit[i] && adj[head][i]){  
        L[head] = i;R[i]=head;L[i]=0;visit[i]=false;  
        return i;  
    }  
    return 0;  
}  
int findTail(){//checked  
    for (int i=1;i<=n;++i)  
    if (visit[i] && adj[tail][i]){  
        R[tail] = i;L[i]=tail;R[i]=0;visit[i]=false;  
        return i;  
    }  
    return 0;  
}  
void print(){  
    int tmp[mn],t = 1,num=1;  
    tmp[num]=1;  
    while (R[t]!=1){  
    t=R[t];tmp[++num]=t;  
    }  
    for (int i=1;i<=num;++i) cout << tmp[i] << " " ;  
    cout << 1 << " " << endl;  
}  
void insert(){int v;//checked  
    //左右两端进行不断的扩展  
    while (v=findHead()) {head = v;listNum ++;}  
    while (v=findTail()) {tail = v;listNum ++;}  
    reverse();//Let哈密顿路成为哈密顿回路  
    if (listNum == n) print();//如果回路中元素满足N个,那么输出  
    else{  
    int tmp = listNum;  
    add();  
    insert();  
    }  
}  
void init(){//checked  
    cin >> n;getchar();  
    for (i = 1;i <= n;++i){  
    getline(cin,s);k=0;  
    for (int j=0;j<s.size();++j)  
        if (s[j]!=‘ ‘) k=k*10+s[j]-‘0‘;  
        else {adj[i][k]=true;k=0;}  
    if (k!=0){  
        adj[i][k]=true;k=0;  
    }  
    }memset(visit,true,sizeof(visit));  
    tail = head = listNum = 1;visit[1]=false;  
}  
int main(){  
    init();  
    insert();  
    return 0;  
}