oj.uz

Submission #394625

# Submission time Handle Problem Language Result Execution time Memory
394625 2021-04-27T06:14:48 Z Sara Network (BOI15_net) C++14
100 / 100
 486 ms 45416 KB 
#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
using namespace __gnu_pbds;
template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag,tree_order_statistics_node_update>;

#define ll long long
#define F first
#define S second
#define pb push_back
#define md ((b + e) >> 1)

const ll N = 5e5 + 5;
const ll LOG = 17;
const ll INF = 1e9 + 5;
const ll MOD = 1e9 + 7;

/*int n, m;
char mat[N][N];
pair <int, int> L[N][N], R[N][N];
pair <int, int> U[N][N], D[N][N];
pair <int, int> dir[4] = {{1, 0}, {0, 1}, {-1, 0}, {0, -1}};
vector < pair <int, int> > g[N][N];
pair <int, int> st, en;

inline bool valid(int x, int y){
    return (1 <= x && x <= n && 1 <= y && y <= m && mat[x][y] == '.');;
}

inline void pre(){
    for (int i = 1; i <= n; i ++){
        for (int j = 1; j <= m; j ++){
            if (mat[i][j] == '#'){
                L[i][j] = {i, j};
                U[i][j] = {i, j};
            }
            else {
                L[i][j] = L[i][j - 1];
                U[i][j] = U[i - 1][j];
            }
        }
    }
    for (int i = n; i >= 1; i --){
        for (int j = m; j >= 1; j --){
            if (mat[i][j] == '#'){
                R[i][j] = {i, j};
                D[i][j] = {i, j};
            }
            else {
                R[i][j] = R[i][j + 1];
                D[i][j] = D[i + 1][j];
            }
        }
    }
    return;
}

int dis[N][N];
queue < pair <int, int> > q;
inline void bfs(){

    for (int i = 1; i <= n; i ++){
        for (int j = 1; j <= m; j ++){
            dis[i][j] = INF;
        }
    }

    q.push({st.F, st.S});
    while (q.size()){
        auto v = q.front();
        for (auto u : g[v.F][v.S]){
            if (dis[v.F][v.S] + 1 < dis[u.F][u.S]){
                dis[u.F][u.S] = dis[v.F][v.S] + 1;
                q.push(u);
            }
        }
    }

    cout << dis[en.F][en.S] << '\n';
    return;
}*/

int n;
int tim;
vector <int> g[N];
vector < pair <int, int> > leaf;
int root = 1;

void dfs(int v, int par = 0){

    tim ++;
    if ((int)g[v].size() == 1){
        leaf.pb({tim, v});
    }

    for (int u : g[v]){
        if (u != par){
            dfs(u, v);
        }
    }

    return;
}

int main() {
    ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);

    cin >> n;
    for (int i = 0; i < n - 1; i ++){
        int u, v;
        cin >> u >> v;
        g[u].pb(v); g[v].pb(u);
    }

    root = 1;
    while ((int)g[root].size() == 1){
        root ++;
    }

    dfs(root);
    sort(leaf.begin(), leaf.end());
    int ans = ((int)leaf.size() + 1) / 2;
    int nim = (int)leaf.size() / 2;

    cout << ans << '\n';
    for (int i = nim; i < (int)leaf.size(); i ++){
        cout << leaf[i - nim].S << ' ' << leaf[i].S << '\n';
    }

    /*cin >> n >> m;

    for (int i = 1; i <= n; i ++){
        for (int j = 1; j <= m; j ++){
            cin >> mat[i][j];
            if (mat[i][j] == 's'){
                st = {i, j};
                mat[i][j] = '.';
            }
            if (mat[i][j] == 'c'){
                en = {i, j};
                mat[i][j] = '.';
            }
        }
    }

    pre();

    for (int i = 1; i <= n; i ++){
        for (int j = 1; j <= m; j ++){
            for (int d = 0; d < 4; d ++){
                int x = i + dir[d].F;
                int y = j + dir[d].S;
                if (valid(x, y)){
                    g[i][j].pb({x, y});
                    g[x][y].pb({i, j};
                }
            }
        }
    }   

    bfs();*/
    
    return 0;
}

Subtask #1
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 11980 KB Output is correct
2 Correct 7 ms 11980 KB Output is correct
3 Correct 7 ms 11980 KB Output is correct
4 Correct 7 ms 11936 KB Output is correct
5 Correct 7 ms 11980 KB Output is correct
6 Correct 7 ms 11980 KB Output is correct
7 Correct 8 ms 11980 KB Output is correct
8 Correct 7 ms 11980 KB Output is correct
9 Correct 7 ms 11980 KB Output is correct
10 Correct 7 ms 12108 KB Output is correct
11 Correct 8 ms 11980 KB Output is correct
12 Correct 8 ms 11980 KB Output is correct
13 Correct 7 ms 11980 KB Output is correct
14 Correct 7 ms 11980 KB Output is correct
15 Correct 8 ms 11980 KB Output is correct
16 Correct 7 ms 12032 KB Output is correct
17 Correct 7 ms 11980 KB Output is correct
18 Correct 9 ms 11948 KB Output is correct
19 Correct 8 ms 11980 KB Output is correct
20 Correct 7 ms 11980 KB Output is correct

Subtask #2
45.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 11980 KB Output is correct
2 Correct 7 ms 11980 KB Output is correct
3 Correct 7 ms 11980 KB Output is correct
4 Correct 7 ms 11936 KB Output is correct
5 Correct 7 ms 11980 KB Output is correct
6 Correct 7 ms 11980 KB Output is correct
7 Correct 8 ms 11980 KB Output is correct
8 Correct 7 ms 11980 KB Output is correct
9 Correct 7 ms 11980 KB Output is correct
10 Correct 7 ms 12108 KB Output is correct
11 Correct 8 ms 11980 KB Output is correct
12 Correct 8 ms 11980 KB Output is correct
13 Correct 7 ms 11980 KB Output is correct
14 Correct 7 ms 11980 KB Output is correct
15 Correct 8 ms 11980 KB Output is correct
16 Correct 7 ms 12032 KB Output is correct
17 Correct 7 ms 11980 KB Output is correct
18 Correct 9 ms 11948 KB Output is correct
19 Correct 8 ms 11980 KB Output is correct
20 Correct 7 ms 11980 KB Output is correct
21 Correct 7 ms 11980 KB Output is correct
22 Correct 9 ms 12108 KB Output is correct
23 Correct 8 ms 12108 KB Output is correct
24 Correct 9 ms 12140 KB Output is correct
25 Correct 8 ms 12048 KB Output is correct
26 Correct 8 ms 12108 KB Output is correct
27 Correct 8 ms 12108 KB Output is correct
28 Correct 8 ms 12108 KB Output is correct
29 Correct 8 ms 12108 KB Output is correct
30 Correct 7 ms 11980 KB Output is correct
31 Correct 9 ms 12108 KB Output is correct
32 Correct 8 ms 11988 KB Output is correct
33 Correct 8 ms 12036 KB Output is correct
34 Correct 9 ms 11980 KB Output is correct
35 Correct 7 ms 12004 KB Output is correct
36 Correct 8 ms 11980 KB Output is correct
37 Correct 7 ms 11980 KB Output is correct
38 Correct 8 ms 12108 KB Output is correct
39 Correct 7 ms 11980 KB Output is correct
40 Correct 8 ms 11980 KB Output is correct
41 Correct 8 ms 11980 KB Output is correct
42 Correct 8 ms 11980 KB Output is correct
43 Correct 7 ms 12108 KB Output is correct
44 Correct 7 ms 11972 KB Output is correct
45 Correct 7 ms 11956 KB Output is correct
46 Correct 8 ms 11980 KB Output is correct
47 Correct 7 ms 11980 KB Output is correct
48 Correct 7 ms 12080 KB Output is correct
49 Correct 8 ms 12108 KB Output is correct
50 Correct 8 ms 11972 KB Output is correct
51 Correct 8 ms 12048 KB Output is correct
52 Correct 8 ms 11980 KB Output is correct
53 Correct 9 ms 12008 KB Output is correct
54 Correct 8 ms 11980 KB Output is correct
55 Correct 8 ms 11980 KB Output is correct
56 Correct 7 ms 11980 KB Output is correct
57 Correct 7 ms 11968 KB Output is correct
58 Correct 8 ms 12108 KB Output is correct

Subtask #3
37.0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 11980 KB Output is correct
2 Correct 7 ms 11980 KB Output is correct
3 Correct 7 ms 11980 KB Output is correct
4 Correct 7 ms 11936 KB Output is correct
5 Correct 7 ms 11980 KB Output is correct
6 Correct 7 ms 11980 KB Output is correct
7 Correct 8 ms 11980 KB Output is correct
8 Correct 7 ms 11980 KB Output is correct
9 Correct 7 ms 11980 KB Output is correct
10 Correct 7 ms 12108 KB Output is correct
11 Correct 8 ms 11980 KB Output is correct
12 Correct 8 ms 11980 KB Output is correct
13 Correct 7 ms 11980 KB Output is correct
14 Correct 7 ms 11980 KB Output is correct
15 Correct 8 ms 11980 KB Output is correct
16 Correct 7 ms 12032 KB Output is correct
17 Correct 7 ms 11980 KB Output is correct
18 Correct 9 ms 11948 KB Output is correct
19 Correct 8 ms 11980 KB Output is correct
20 Correct 7 ms 11980 KB Output is correct
21 Correct 7 ms 11980 KB Output is correct
22 Correct 9 ms 12108 KB Output is correct
23 Correct 8 ms 12108 KB Output is correct
24 Correct 9 ms 12140 KB Output is correct
25 Correct 8 ms 12048 KB Output is correct
26 Correct 8 ms 12108 KB Output is correct
27 Correct 8 ms 12108 KB Output is correct
28 Correct 8 ms 12108 KB Output is correct
29 Correct 8 ms 12108 KB Output is correct
30 Correct 7 ms 11980 KB Output is correct
31 Correct 9 ms 12108 KB Output is correct
32 Correct 8 ms 11988 KB Output is correct
33 Correct 8 ms 12036 KB Output is correct
34 Correct 9 ms 11980 KB Output is correct
35 Correct 7 ms 12004 KB Output is correct
36 Correct 8 ms 11980 KB Output is correct
37 Correct 7 ms 11980 KB Output is correct
38 Correct 8 ms 12108 KB Output is correct
39 Correct 7 ms 11980 KB Output is correct
40 Correct 8 ms 11980 KB Output is correct
41 Correct 8 ms 11980 KB Output is correct
42 Correct 8 ms 11980 KB Output is correct
43 Correct 7 ms 12108 KB Output is correct
44 Correct 7 ms 11972 KB Output is correct
45 Correct 7 ms 11956 KB Output is correct
46 Correct 8 ms 11980 KB Output is correct
47 Correct 7 ms 11980 KB Output is correct
48 Correct 7 ms 12080 KB Output is correct
49 Correct 8 ms 12108 KB Output is correct
50 Correct 8 ms 11972 KB Output is correct
51 Correct 8 ms 12048 KB Output is correct
52 Correct 8 ms 11980 KB Output is correct
53 Correct 9 ms 12008 KB Output is correct
54 Correct 8 ms 11980 KB Output is correct
55 Correct 8 ms 11980 KB Output is correct
56 Correct 7 ms 11980 KB Output is correct
57 Correct 7 ms 11968 KB Output is correct
58 Correct 8 ms 12108 KB Output is correct
59 Correct 447 ms 31212 KB Output is correct
60 Correct 471 ms 33332 KB Output is correct
61 Correct 8 ms 11980 KB Output is correct
62 Correct 8 ms 11980 KB Output is correct
63 Correct 318 ms 29484 KB Output is correct
64 Correct 10 ms 12492 KB Output is correct
65 Correct 18 ms 13900 KB Output is correct
66 Correct 153 ms 28308 KB Output is correct
67 Correct 470 ms 44484 KB Output is correct
68 Correct 481 ms 45416 KB Output is correct
69 Correct 15 ms 12876 KB Output is correct
70 Correct 103 ms 19740 KB Output is correct
71 Correct 328 ms 37040 KB Output is correct
72 Correct 336 ms 36112 KB Output is correct
73 Correct 88 ms 17604 KB Output is correct
74 Correct 459 ms 32048 KB Output is correct
75 Correct 33 ms 14784 KB Output is correct
76 Correct 353 ms 36700 KB Output is correct
77 Correct 337 ms 37028 KB Output is correct
78 Correct 32 ms 15300 KB Output is correct
79 Correct 486 ms 42228 KB Output is correct
80 Correct 11 ms 12180 KB Output is correct
81 Correct 108 ms 19688 KB Output is correct
82 Correct 395 ms 34564 KB Output is correct
83 Correct 446 ms 31960 KB Output is correct
84 Correct 442 ms 31928 KB Output is correct
85 Correct 443 ms 31964 KB Output is correct
86 Correct 480 ms 33508 KB Output is correct
87 Correct 434 ms 33412 KB Output is correct