oj.uz

Submission #25720

# Submission time Handle Problem Language Result Execution time Memory
25720 2017-06-23T19:04:49 Z gs14004 Pipes (CEOI15_pipes) C++11
70 / 100
 497 ms 18896 KB 
#include <cstdio>
#include <vector>
#include <algorithm>
using namespace std;
typedef pair<int,int> pi;
  
struct disj{
    int pa[100005];
    void init(int n){
        for(int i=0; i<=n; i++) pa[i] = i;
    }
    int find(int x){
        return pa[x] = (pa[x] == x ? x : find(pa[x]));
    }
    bool uni(int p, int q){
        p = find(p);
        q = find(q);
        if(p == q) return 0;
        pa[q] = p;
        find(q);
        return 1;
    }
}disj1, disj2;
  
int n, m;
vector<pi> tree, bri;
vector<int> graph[100005];
vector<pi> procession[100005];
  
int par[100005][17], dep[100005];
bool vis[100005];
  
void dfs(int x, int pa){
    vis[x] = 1;
    par[x][0] = pa;
    for(int i=1; i<17; i++){
        par[x][i] = par[par[x][i-1]][i-1];
    }
    for (auto &i : graph[x]){
        if(i == pa) continue;
        dep[i] = dep[x] + 1;
        dfs(i,x);
    }
}
  
int lca(int x, int y){
    if(dep[x] < dep[y]) swap(x,y);
    int dx = dep[x] - dep[y];
    for(int i=0; i<17; i++){
        if((dx >> i) & 1) x = par[x][i];
    }
    for(int i=16; i>=0; i--){
        if(par[x][i] != par[y][i]){
            x = par[x][i];
            y = par[y][i];
        }
    }
    if(x != y) x = par[x][0];
    return x;
}
  
int up[100005];
  
void dfs2(int x, int pa){
    for (auto &i : graph[x]){
        if(i == pa) continue;
        dfs2(i,x);
        up[x] = max(up[x], up[i] - 1);
    }
    if(pa != 0 && up[x] == 0) printf("%d %d\n",pa,x);
}
int main(){
    scanf("%d %d\n",&n,&m);
    disj1.init(n);
    disj2.init(n);
    while(m--){
        int u = 0, v = 0;
        char str[15];
        fgets(str,15,stdin);
        int pos = 0;
        while(str[pos] != ' '){
            u = (10 * u) + (str[pos] - '0');
            pos++;
        }
        pos++;
        while(str[pos] != '\n' && str[pos]){
            v = (10 * v) + (str[pos] - '0');
            pos++;
        }
        if(disj1.uni(u,v)){
            tree.push_back(pi(u,v));
        }
        else if(disj2.uni(u,v)){
            bri.push_back(pi(u,v));
        }
    }
    for(auto &i : tree){
        graph[i.first].push_back(i.second);
        graph[i.second].push_back(i.first);
    }
    for(auto &i : bri){
        procession[disj1.find(i.first)].push_back(i);
    }
    for(int i=1; i<=n; i++){
        if(!vis[i]){
            int pos = disj1.find(i);
            dfs(pos,0);
            for (auto &i : procession[pos]){
                int l = lca(i.first,i.second);
                up[i.first] = max(up[i.first],dep[i.first] - dep[l]);
                up[i.second] = max(up[i.second],dep[i.second] - dep[l]);
            }
            dfs2(pos,0);
        }
    }
}

Compilation message

pipes.cpp: In function 'int main()':
pipes.cpp:73:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d\n",&n,&m);
     ~~~~~^~~~~~~~~~~~~~~~~
pipes.cpp:79:14: warning: ignoring return value of 'char* fgets(char*, int, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
         fgets(str,15,stdin);
         ~~~~~^~~~~~~~~~~~~~

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 4992 KB Output is correct
2 Correct 6 ms 4992 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 5732 KB Output is correct
2 Correct 8 ms 5660 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 36 ms 5564 KB Output is correct
2 Correct 35 ms 5468 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 55 ms 6492 KB Output is correct
2 Correct 63 ms 6436 KB Output is correct

Subtask #5
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 104 ms 8436 KB Output is correct
2 Correct 102 ms 9088 KB Output is correct

Subtask #6
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 187 ms 14768 KB Output is correct
2 Correct 180 ms 14772 KB Output is correct

Subtask #7
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 272 ms 16288 KB Output is correct
2 Correct 249 ms 15976 KB Output is correct

Subtask #8
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 373 ms 18824 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 437 ms 18896 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 497 ms 18148 KB Memory limit exceeded (if you are sure your verdict is not MLE, please contact us)
2 Halted 0 ms 0 KB -