#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;
using pii = pair<int, int>;
using ppi = pair<pii, int>;
#define forn(i, n) for(int i=0; i<(int)n; ++i)
#define PB push_back
#define F first
#define S second
const int MAXN=100010;
int n, w, cou[2*MAXN];
bool ans[2*MAXN];
pii edges[2*MAXN], g[MAXN][4], pt[MAXN];
vector<ppi> remaining;
int getDir(int a, int b){
pii pa = pt[a], pb = pt[b];
if(pa.F == pb.F) return pa.S < pb.S? 1 : 3;
else return pa.F < pb.F? 0 : 2;
}
int main(){
scanf("%d", &n);
forn(i, n) scanf("%d %d", &pt[i].F, &pt[i].S);
forn(i, n) forn(j, 4) g[i][j] = {-1, -1};
scanf("%d", &w);
remaining.resize(w);
forn(i, w){
int a, b; scanf("%d %d", &a, &b); --a, --b;
if(pt[a].F<pt[b].F) swap(a, b);
edges[i]={a, b};
remaining[i]={edges[i], i};
g[a][getDir(a, b)] = {b, i};
g[b][getDir(b, a)] = {a, i};
}
sort(remaining.begin(), remaining.end(), [](ppi a, ppi b){
return pt[a.F.F].F < pt[b.F.F].F;
});
while(!remaining.empty()){
ppi ed = remaining.back();
remaining.pop_back();
if(cou[ed.S]) continue;
bool stop = false;
int cur = ed.F.F, dir=2, ind, fin, finDir;
vector<int> toClear;
while(true){
dir = (dir+3)&3;
while(g[cur][dir].F==-1) dir = (dir+1)&3;
ind = g[cur][dir].S;
if(!stop) fin = ind, finDir = dir;
if(ind==fin && finDir==dir && stop) break;
stop = true;
cur = g[cur][dir].F;
toClear.PB(ind);
}
for(int e:toClear){
cou[e]++;
int a = edges[e].F, b = edges[e].S;
if(cou[e]==1){
g[a][getDir(a, b)] = {-1, -1};
g[b][getDir(b, a)] = {-1, -1};
}
else ans[e]=true;
}
}
int total=0;
forn(i, w) if(ans[i]) ++total;
printf("%d\n", total);
forn(i, w) if(ans[i]) printf("%d\n", i+1);
}
Compilation message
flood.cpp: In function 'int main()':
flood.cpp:25:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
25 | scanf("%d", &n);
| ~~~~~^~~~~~~~~~
flood.cpp:26:21: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
26 | forn(i, n) scanf("%d %d", &pt[i].F, &pt[i].S);
| ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
flood.cpp:28:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
28 | scanf("%d", &w);
| ~~~~~^~~~~~~~~~
flood.cpp:31:24: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
31 | int a, b; scanf("%d %d", &a, &b); --a, --b;
| ~~~~~^~~~~~~~~~~~~~~~~
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
212 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
212 KB |
Output is correct |
2 |
Correct |
1 ms |
212 KB |
Output is correct |
3 |
Correct |
1 ms |
212 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
340 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
340 KB |
Output is correct |
2 |
Correct |
1 ms |
340 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
340 KB |
Output is correct |
2 |
Correct |
1 ms |
340 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
340 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
340 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
340 KB |
Output is correct |
2 |
Correct |
1 ms |
340 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
340 KB |
Output is correct |
2 |
Correct |
1 ms |
340 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
11 ms |
1860 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
41 ms |
5768 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
38 ms |
5928 KB |
Output is correct |
2 |
Incorrect |
72 ms |
8164 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
66 ms |
7472 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
82 ms |
8036 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |