gym/102021/J GCPC18 模拟拼图

模拟拼图

题意：

　　给定n块拼图，每个拼图为四方形，对应四条边有四个数字，如果为0，表示这个边是在边界的，其他数字表示和另一个拼图的一条边相接。保证每个非零数只出现两次。

思路：

　　模拟，但是要注意几个情况，第一就是只有一行或一列的时候，对于0的判断，还有就是拼图的个数要和n相等。

#include <algorithm>
#include  <iterator>
#include  <iostream>
#include   <cstring>
#include   <cstdlib>
#include   <iomanip>
#include    <bitset>
#include    <cctype>
#include    <cstdio>
#include    <string>
#include    <vector>
#include     <stack>
#include     <cmath>
#include     <queue>
#include      <list>
#include       <map>
#include       <set>
#include   <cassert>

using namespace std;
#define lson (l , mid , rt << 1)
#define rson (mid + 1 , r , rt << 1 | 1)
#define debug(x) cerr << #x << " = " << x << "\n";
#define pb push_back
#define pq priority_queue

typedef long long ll;
typedef unsigned long long ull;
//typedef __int128 bll;
typedef pair<ll ,ll > pll;
typedef pair<int ,int > pii;
typedef pair<int,pii> p3;

//priority_queue<int> q;//这是一个大根堆q
//priority_queue<int,vector<int>,greater<int> >q;//这是一个小根堆q
#define fi first
#define se second
//#define endl '\n'

#define OKC ios::sync_with_stdio(false);cin.tie(0)
#define FT(A,B,C) for(int A=B;A <= C;++A)  //用来压行
#define REP(i , j , k)  for(int i = j ; i <  k ; ++i)
#define max3(a,b,c) max(max(a,b), c);
#define min3(a,b,c) min(min(a,b), c);
//priority_queue<int ,vector<int>, greater<int> >que;

const ll mos = 0x7FFFFFFF;  //
const ll nmos = 0x80000000;  //-2147483648
const int inf = 0x3f3f3f3f;
const ll inff = 0x3f3f3f3f3f3f3f3f; //
const int mod = ;
const double esp = 1e-;
const double PI=acos(-1.0);
const double PHI=0.61803399;    //黄金分割点
const double tPHI=0.38196601;

template<typename T>
inline T read(T&x){
    x=;int f=;char ch=getchar();
    while (ch<''||ch>'') f|=(ch=='-'),ch=getchar();
    while (ch>=''&&ch<='') x=x*+ch-'',ch=getchar();
    return x=f?-x:x;
}
/*-----------------------showtime----------------------*/

            const int maxn = 3e5+;
            int a[maxn][];
            int mp[maxn*][],vis[maxn];
            vector<int>res[maxn];

            int get(int id,int nd1,int nd2){
                int res = -;
                for(int i=; i<=; i++){
                    if(a[id][i] == nd1 && a[id][i+] == nd2)
                    {
                        res = i;
                    }
                }
                return res;
            }

int main(){
            int n;
            scanf("%d", &n);
            int flag =, st = -;
            for(int i=; i<=n; i++){
                scanf("%d%d%d%d", &a[i][], &a[i][], &a[i][], &a[i][]);
                a[i][] = a[i][];
                a[i][] = a[i][];
                a[i][] = a[i][];
                a[i][] = a[i][];
                int cnt = ;
                for(int j=; j<=; j++){
                    if(a[i][j] == ) cnt++;
                    else {
                        if(mp[a[i][j]][] == ) mp[a[i][j]][] = i;
                        else if(mp[a[i][j]][] == )mp[a[i][j]][] = i;
//                        else { puts("impossible");return 0;}
                    }
                }
                if(cnt >=  && st == -){
                    int tmp = get(i, , );
                 //   debug(tmp);
                    if(tmp >=) st = i,a[st][] = tmp;
                }
            }

            if(st == -) {
                puts("impossible");
                return ;
            }
            int h=,w=;
            w = ;
            res[].pb(st);
            vis[st] = ;
            for(;;){
                int id = res[][w];
                int num = a[id][a[id][] + ];
                if(num == )  break;
                int nx = -;
                if(vis[mp[num][]] == ) nx = mp[num][];
                else if(vis[mp[num][]] == ) nx = mp[num][];
                if(nx == -) {puts("impossible");return ;}

                int tmp = get(nx, , num);
                if(tmp == -) {puts("impossible");return ;}

                a[nx][] = tmp;
                res[].pb(nx); w++;
                vis[nx] = ;
            }

             for(; ;){
                int id = res[h][];
                int num = a[id][a[id][] + ];
            //    debug(num);
                if(num == ) break;
                int nx = -;
                if(vis[mp[num][]] == ) nx = mp[num][];
                else if(vis[mp[num][]] == ) nx = mp[num][];

                if(nx == -) {puts("impossible");return ;}

                int tmp = get(nx, num, );
              //  debug(nx);
                if(tmp == -) {puts("impossible");return ;}

                a[nx][] = tmp;
                h++;
                res[h].pb(nx);
                vis[nx] = ;
            }

       //    cout<<h<<" "<<w<<endl;
            for(int i=; i<=h; i++){
                for(int j=; j<=w; j++){
                    int num1id = res[i-][j];
                    int num2id = res[i][j-];

                    int num1 = a[num1id][a[num1id][] + ];
                    int num2 = a[num2id][a[num2id][] + ];
                 //   cout<<num1id<<" "<<num2id<<endl;
                 //   cout<<num1<<" "<<num2<<endl;
                    if(num1 ==  || num2 == ) {puts("impossible"); return ;}
                    int nx1 = -, nx2 = -;

                    if(vis[mp[num1][]] == ) nx1 = mp[num1][];
                    else if(vis[mp[num1][]] == ) nx1 = mp[num1][];

                    if(vis[mp[num2][]] == ) nx2= mp[num2][];
                    else if(vis[mp[num2][]] == ) nx2 = mp[num2][];

                    if(nx1 == - || nx2 == -) {puts("impossible");return ;}
                    if(nx1 != nx2) {puts("impossible");return ;}

                    int tmp = get(nx1, num1, num2);

                    if(tmp == -) {puts("impossible");return ;}

                    a[nx1][] = tmp;
                    res[i].pb(nx1);
                    vis[nx1] = ;
                    if(i==h) if(a[nx1][tmp + ] != ) {puts("impossible");return ;}
                    if(j==w) if(a[nx1][tmp + ] != ) {puts("impossible");return ;}

                }
            }

            if((h+) * (w + ) != n)
               {puts("impossible");return ;}

            if(h == ) {
                for(int i=; i<=w; i++) {
                    int id = res[][i];
                    int t = a[id][];
                    if(a[id][t+] != )  {puts("impossible");return ;}
                    if(i == w && a[id][t+] != )  {puts("impossible");return ;}
                }
            }

            if(w == ){
                for(int i=; i<=h; i++){
                     int id = res[i][];
                    int t = a[id][];
                    if(a[id][t+] != )  {puts("impossible");return ;}
                    if(i == h && a[id][t+] != )  {puts("impossible");return ;}

                }

            }
            printf("%d %d\n", h+, w+);
            for(int i=; i<=h; i++){
                for(int j=; j<=w; j++){
                    printf("%d ", res[i][j]);
                }
                puts("");
            }
            return   ;
}