1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
// Mateusz Kurek, PA 2014
// 5B FIO

#include<cstdio>
#include<cmath>
#include<cstdlib>
#include<algorithm>
#include<vector>
#include<string>
#include<list>
#include<deque>
#include<map>
#include<set>
#include<queue>
#include<stack>
#include<utility>
#include<sstream>
#include<cstring>
#include <string>
#include <unistd.h>

//#include <iostream>

using namespace std;

#define REP(i,v)for(int i=0;i<(v);++i)
#define FOR(i,x,v)for(int i=x;i<=(v);++i)
#define FORD(i,x,v)for(int i=x;i>=(v);--i)
#define VAR(v,n) __typeof(n) v = (n)
#define FOREACH(i,c) for(VAR(i,(c).begin()); i != (c).end(); ++i)
#define ALL(c) (c).begin(), c.end()
#define PB push_back
#define SZ size
#define MP make_pair
#define FI first
#define SE second
#define CL clear()
#define RS resize
#define INFTY 1000000001
#define EPS 10e-9
#define SIZE(x) ((int)(x).size())

typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<bool> VB;
typedef pair<int,int> PII;
typedef long long LL;
typedef vector<string> VS;

void show(PII p)
{printf("(%d %d)\n",p.FI,p.SE);}

void show(VI e)
{REP(i,SIZE(e)) printf("%d ",e[i]); printf("\n");}

void show(vector<PII> e)
{REP(i,SIZE(e)) printf("(%d %d) ",e[i].FI,e[i].SE); printf("\n");}

void show(VS e)
{REP(i,SIZE(e)) printf("%s\n",e[i].c_str());}

void show(VVI e)
{REP(i,SIZE(e)) show(e[i]);}

#define MAXN 100001
#define MAXN2 300000
const int X2_ADD = 500000;

int x1s[MAXN2], x2s[MAXN2], y1s[MAXN2], y2s[MAXN2];

struct picompcls{
    bool operator()(const int &l, const int &r) const{
        int va, vb, vc, vd;
        if(l >= X2_ADD){
            va = x2s[l % X2_ADD];
            vc = x1s[l % X2_ADD];
        }
        else{
            va = x1s[l % X2_ADD];
            vc = x2s[l % X2_ADD];
        }

        if(r >= X2_ADD){
            vb = x2s[r-X2_ADD];
            vd = x1s[r % X2_ADD];
        }
        else{
            vb = x1s[r % X2_ADD];
            vd = x2s[r % X2_ADD];
        }

        if(va == vb){
            if(vc == vd){
                if(y1s[l % X2_ADD] == y1s[r % X2_ADD]){
                    return y2s[l%X2_ADD] < y2s[r % X2_ADD];
                }
                return y1s[l % X2_ADD] < y1s[r % X2_ADD];
            }
            return vc < vd;
        }
        return va < vb;
    }
};



bool resultcomp(const int &a, const int &b){
    if(x1s[a] == x1s[b]){
        if(x2s[a] == x2s[b]){
            if(y1s[a] == y1s[b]){
                return y2s[a] < y2s[b];
            }
            return y1s[a] < y1s[b];
        }
        return x2s[a] < x2s[b];
    }
    return x1s[a] < x1s[b];
}

string printpl(int x){
    char buf[100];
    sprintf(buf, "(%d, %d, %d, %d)", x1s[x], x2s[x], y1s[x], y2s[x]);
    string result = buf;
    return result;
}

int main(){
    int n;
    int x1, x2, y1, y2, counter, index1, index2;
    // pl pl1, pl2, pl3;
    VI to_add, to_remove;
    bool found;
    set<int, picompcls> pls_set;
    set<int, picompcls>::iterator it1, it2;
    pair<set<int>::iterator, bool> res;
    bool still_in_use[MAXN2];

    scanf("%d", &n);
    REP(i, n){
        scanf("%d %d %d %d", &x1, &x2, &y1, &y2);
        // pl1 = {.x1=x1, .x2=x2, .y1=y1, .y2=y2};
        x1s[i] = x1;
        x2s[i] = x2;
        y1s[i] = y1;
        y2s[i] = y2;

        res = pls_set.insert(i);
        // if(!res.second){
        //     printf("%d not inserted\n", i);
        // }
        res = pls_set.insert(i+X2_ADD);
        // if(!res.second){
        //     printf("%d not inserted\n", i + X2_ADD);
        // }
        still_in_use[i] = true;
    }
    counter = n;
    // printf("pls set: ");
    // for(it1=pls_set.begin(); it1 != pls_set.end(); ++it1){
    //     printf("%d ", *it1);
    // }
    // printf("\n\n");
    do{
        // printf("clearing to_add\n");
        to_add.clear();
        // printf("clearing to_remove\n");
        to_remove.clear();
        // printf("testing\n");
        for(it1=pls_set.begin(); it1 != pls_set.end();){
            found = false;
            index1 = (*it1) % X2_ADD;
            if(*it1 < X2_ADD && still_in_use[index1]){
                // pl1 = pls[index1];
                // printf("looking for intersection with %d (%s)\n", index1, printpl(index1).c_str());
                for(it2=pls_set.lower_bound(index1); it2 != pls_set.end(); ++it2){
                    index2 = (*it2) % X2_ADD;
                    // pl2 = pls[index2];
                    // if((*it2 >= X2_ADD && x2s[index2] >= x2s[index1]) || (*it2 < X2_ADD && x1s[index2] >= x2s[index1])) {
                    //     break;
                    // }
                    if(index1 != index2 && still_in_use[index2]){
                        // printf("testing %d (%s)\n", index2, printpl(index2).c_str());

                        // if((y1s[index2] > y1s[index1] && y1s[index2] <= y2s[index1]) || ((y2s[index2] >= y1s[index1] && y2s[index2] < y2s[index1])) || (y1s[index2] <= y1s[index1] && y2s[index2] >= y2s[index1])){
                        // if((y1s[index2] > y1s[index1] && y2s[index2] < y1s[index1]) || (y1s[index2] >= y1s[index1] && y2s[index2] < y1s[index1]) || (y1s[index2] > y1s[index1] && y2s[index2] <= y1s[index1]) || (y1s[index2] <= y1s[index1] && y2s[index2] >= y2s[index1])){
                        if(x1s[index1] < x2s[index2] && x2s[index1] > x1s[index2] && y1s[index1] < y2s[index2] && y2s[index1] > y1s[index2]){
                            // printf("found intersection with %d (%s)\n", index2, printpl(index2).c_str());
                            // pl3 = {.x1=min(pl1.x1, pl2.x1), .x2=max(pl1.x2, pl2.x2), .y1=min(pl1.y1, pl2.y1), .y2=max(pl1.y2, pl2.y2)};
                            // pls.push_back(pl3);
                            x1s[counter] = min(x1s[index1], x1s[index2]);
                            x2s[counter] = max(x2s[index1], x2s[index2]);
                            y1s[counter] = min(y1s[index1], y1s[index2]);
                            y2s[counter] = max(y2s[index1], y2s[index2]);
                            // printf("adding %d (%s)\n", counter, printpl(counter).c_str());
                            to_add.push_back(counter++);
                            still_in_use[index2] = false;
                            to_remove.push_back(index2);
                            found = true;
                            break;
                        }
                    }
                }
            }
            if(found){
                still_in_use[index1] = false;
                // pls_set.erase(it1++);
                to_remove.push_back(index1);
            }
            else{
                ++it1;
            }
        }
        // printf("removing from pls_set\n");
        // remove
        for(int i=0;i<to_remove.size();i++){
            // printf("removing %d\n", to_remove[i] % X2_ADD);
            // if(to_remove[i] == 303){
            //     printf("pls_set: ");
            //     for(it1=pls_set.begin(); it1 != pls_set.end(); ++it1){
            //         printf("%d ", *it1);
            //     }
            // }
            // printf("\n");
            it1 = pls_set.find(to_remove[i] % X2_ADD);
            // if(to_remove[i] == 303){
            //     printf("it != pls_set.end(): %d\n", it1 != pls_set.end());
            // }
            pls_set.erase(it1);
            // printf("removing %d\n", to_remove[i] % X2_ADD + X2_ADD);
            it1 = pls_set.find((to_remove[i] % X2_ADD) + X2_ADD);
            pls_set.erase(it1);
        }
        // printf("after remove; adding new to pls_set\n");
        // add
        for(int i=0;i<to_add.size();i++){
            // printf("adding %d (%s) to pls_set\n", to_add[i], printpl(to_add[i]).c_str());
            pls_set.insert(to_add[i]);
            pls_set.insert(to_add[i] + X2_ADD);
            still_in_use[to_add[i]] = true;
        }


        // printf("after adding new to pls_set\n");
        // printf("after intersecting\npls_set: ");
        // for(it1=pls_set.begin(); it1 != pls_set.end(); ++it1){
        //     printf("%d ", *it1);
        // }
        // printf("\nstill in use:\n");
        // for(int i=0;i<counter;i++){
        //     if(still_in_use[i]){
        //         printf("%d (%s) ", i, printpl(i).c_str());
        //     }
        // }
        // printf("\n\n");


    }while(to_add.size() > 0);
    // printf("after final intersecting\n");

    VI result;
    for(it1=pls_set.begin(); it1 != pls_set.end(); ++it1){
        index1 = (*it1) % X2_ADD;
        if(still_in_use[index1]){
            result.push_back(index1);
            still_in_use[index1] = false;
        }
    }
    // printf("sorting\n");
    // for(it1=pls_set.begin(); it1 != pls_set.end(); ++it1){
    //     printf("%d (%s)", *it1, printpl(*it1));
    // }
    // printf("\n");
    sort(result.begin(), result.end(), resultcomp);
    printf("%d\n", result.size());
    for(int i=0;i<result.size();i++){
        // pl1 = pls[result[i]];
        printf("%d %d %d %d\n", x1s[result[i]], x2s[result[i]], y1s[result[i]], y2s[result[i]]);
    }
    // printf("end\n");
    // to_add.clear();
    // to_remove.clear();
    // still_in_use.clear();
    // pls_set.clear();
    // pls.clear();
    // result.clear();
    return 0;
}