oj.uz

Submission #246461

# Submission time Handle Problem Language Result Execution time Memory
246461 2020-07-09T11:27:53 Z dantoh000 Pipes (CEOI15_pipes) C++14
50 / 100
 1835 ms 46200 KB 
#include <utility>
#include <vector>
#include <algorithm>
#include <cstdio>
#include <set>
#include <unordered_set>
using namespace std;
typedef pair<int,int> ii;
int n,m;
int d[100005], pa[100005], sz[100005];
vector<int> G[100005];
unordered_set<int> bad[100005];
struct ufds{
    int p[100005];
    ufds(){
        for (int i = 0; i <= 100000; i++) p[i] = i;
    }
    inline int find(int x){
        return p[x] == x ? x : p[x] = find(p[x]);
    }
    inline void un(int x, int y){
        p[x] = y;
    }
} u1 = ufds(), u2 = ufds();
void dfs(int u, int p){
    ///join at side bad
    u2.p[u] = u;
    pa[u] = p;
	for (auto v : G[u]){
		if (v == p) continue;
		else{
            d[v] = d[u]+1;
            dfs(v,u);
		}
	}
}

int main(){
    scanf("%d%d",&n,&m);
    for (int i = 1; i <= n; i++) sz[i] = 1;
    for (int i = 0; i < m; i++){
        int u,v;
        scanf("%d%d",&u,&v);
        int pu = u1.find(u), pv = u1.find(v);
        //printf("%d -> %d, %d -> %d\n",u,pu,v,pv);
        if (pu == pv){
            //printf("update path %d %d\n",u,v);
            ///make all edges along this path bad
            ///all edges along path are only changed once, amortised O()
            u = u2.find(u), v = u2.find(v);
            while (u != v){
                if (d[u] < d[v]) swap(u,v);
                bad[min(u,pa[u])].insert(max(u,pa[u]));
                //printf("bad %d %d\n",u,pa[u]);
              	u2.un(u,pa[u]);
                u = pa[u];
                u = u2.find(u);
            }
        }
        else{

            //printf("join %d %d\n",u,v);
            ///join the two components
            if (sz[pu] < sz[pv]){
                swap(pu,pv);
                swap(u,v);
            }
            ///join small v to big u
            u1.un(pv,pu);
            sz[pu] += sz[pv];
            ///add edge
            G[u].push_back(v);
            G[v].push_back(u);
            ///restart dfs
            d[v] = d[u]+1;
            dfs(v,u);

        }
    }
    for (int u = 1; u <= n ;u++){
        for (auto v : G[u]){
            if (v > u && bad[u].find(v) == bad[u].end()){
                printf("%d %d\n",u,v);
            }
        }
    }
}

Compilation message

pipes.cpp: In function 'int main()':
pipes.cpp:39:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d",&n,&m);
     ~~~~~^~~~~~~~~~~~~~
pipes.cpp:43:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d",&u,&v);
         ~~~~~^~~~~~~~~~~~~~

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 10 ms 8960 KB Output is correct
2 Correct 10 ms 8960 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 14 ms 9344 KB Output is correct
2 Correct 16 ms 9344 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 152 ms 9344 KB Output is correct
2 Correct 159 ms 9336 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 258 ms 9856 KB Output is correct
2 Correct 303 ms 9976 KB Output is correct

Subtask #5
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 419 ms 11256 KB Output is correct
2 Correct 358 ms 12024 KB Output is correct

Subtask #6
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 595 ms 35576 KB Memory limit exceeded (if you are sure your verdict is not MLE, please contact us)
2 Halted 0 ms 0 KB -

Subtask #7
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 863 ms 23544 KB Memory limit exceeded (if you are sure your verdict is not MLE, please contact us)
2 Halted 0 ms 0 KB -

Subtask #8
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 1186 ms 32536 KB Memory limit exceeded (if you are sure your verdict is not MLE, please contact us)
2 Halted 0 ms 0 KB -

Subtask #9
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 1468 ms 46200 KB Memory limit exceeded (if you are sure your verdict is not MLE, please contact us)
2 Halted 0 ms 0 KB -

Subtask #10
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 1835 ms 32708 KB Memory limit exceeded (if you are sure your verdict is not MLE, please contact us)
2 Halted 0 ms 0 KB -