oj.uz

Submission #256187

# Submission time Handle Problem Language Result Execution time Memory
256187 2020-08-02T11:11:34 Z giorgikob Mousetrap (CEOI17_mousetrap) C++14
100 / 100
 1493 ms 188792 KB 
#include<bits/stdc++.h>
#define ll long long
#define ff first
#define ss second
#define pb push_back
using namespace std;

const int N = 1e6 + 5;

int n, m, t;
int w[N], P[N];
vector<int> gr[N];
vector<pair<int,int>> L;
vector<int> path;

void dfs(int x, int p){
        P[x] = p;
        for(auto to : gr[x]){
                if(to == p) continue;
                dfs(to, x);
        }
}

int CNT;

void count_w(int x, int cnt, int dep){

        if(gr[x].size() == 1){
                w[x] = cnt + dep;
                return ;
        }
        cnt += gr[x].size() - 2;
        vector<int>v;
        for(int to : gr[x]){
                if(to == P[x]) continue;
                count_w(to, cnt, dep+1);
                v.pb(w[to]);
        }
        cnt -= gr[x].size() - 2;
        sort(v.rbegin(),v.rend());
        if(v.size() == 1){
                w[x] = 1 + dep + cnt;
        } else {
                w[x] = v[1];
        }
}

inline bool check(int x){
        int B = 0;
        for(int i = 0; i < L.size(); i++){
                auto p = L[i];
                //if(i == L.size() - 1) return p.ss + B <= x;
                if(B >= p.ff){
                        if(p.ss + B > x) return false;
                } else
                if(p.ss + B > x){
                        B++;
                }
                if(B > x) return false;
        }

        return true;
}

int main(){

        ios::sync_with_stdio(0);
        cin >> n >> t >> m;

        for(int i = 1; i < n; i++){
                int x, y;
                cin >> x >> y;
                gr[x].pb(y);
                gr[y].pb(x);
        }

        dfs(t,0);

        int ver = m;
        while(ver != t){
                path.pb(ver);
                ver = P[ver];
        }

        reverse(path.begin(), path.end());

        for(int i = 0; i < path.size(); i++){
                int x = path[i];
                int k = 3;
                if(i == path.size() - 1) k--;
                CNT += max(0, (int)gr[x].size() - k);
                //cout << CNT << endl;
                for(int to : gr[x]){
                        if(to == P[x]) continue;
                        if(path.size() - 1 != i && to == path[i+1]) continue;
                        count_w(to, CNT, 1);
                        L.pb({path.size() - i, w[to]});
                }
                if((int)gr[x].size() >= 3)CNT++;
        }


        //for(int i = 1; i <= n; i++) cout << w[i] << " "; cout << endl;

        sort(L.begin(), L.end());

        //for(auto p : L) cout << p.ff << " " << p.ss << endl;

        int l = 0, r = 1e6, answer = -1;
        while(l <= r) {
                int mid = l+r; mid >>= 1;
                if(check(mid)){
                        answer = mid;
                        r = mid - 1;
                } else {
                        l = mid + 1;
                }
        }

        cout << answer << endl;

}

Compilation message

mousetrap.cpp: In function 'bool check(int)':
mousetrap.cpp:50:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int i = 0; i < L.size(); i++){
                        ~~^~~~~~~~~~
mousetrap.cpp: In function 'int main()':
mousetrap.cpp:87:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int i = 0; i < path.size(); i++){
                        ~~^~~~~~~~~~~~~
mousetrap.cpp:90:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
                 if(i == path.size() - 1) k--;
                    ~~^~~~~~~~~~~~~~~~~~
mousetrap.cpp:95:44: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
                         if(path.size() - 1 != i && to == path[i+1]) continue;
                            ~~~~~~~~~~~~~~~~^~~~

Subtask #1
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 15 ms 23808 KB Output is correct
2 Correct 17 ms 23808 KB Output is correct
3 Correct 15 ms 23808 KB Output is correct
4 Correct 17 ms 23808 KB Output is correct
5 Correct 15 ms 23808 KB Output is correct
6 Correct 19 ms 23808 KB Output is correct
7 Correct 17 ms 23808 KB Output is correct
8 Correct 15 ms 23808 KB Output is correct
9 Correct 14 ms 23808 KB Output is correct
10 Correct 14 ms 23788 KB Output is correct

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 483 ms 63992 KB Output is correct
2 Correct 406 ms 60068 KB Output is correct
3 Correct 1422 ms 65036 KB Output is correct
4 Correct 487 ms 45108 KB Output is correct
5 Correct 1066 ms 65196 KB Output is correct
6 Correct 1246 ms 65484 KB Output is correct

Subtask #3
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 15 ms 23808 KB Output is correct
2 Correct 17 ms 23808 KB Output is correct
3 Correct 15 ms 23808 KB Output is correct
4 Correct 17 ms 23808 KB Output is correct
5 Correct 15 ms 23808 KB Output is correct
6 Correct 19 ms 23808 KB Output is correct
7 Correct 17 ms 23808 KB Output is correct
8 Correct 15 ms 23808 KB Output is correct
9 Correct 14 ms 23808 KB Output is correct
10 Correct 14 ms 23788 KB Output is correct
11 Correct 21 ms 23884 KB Output is correct
12 Correct 15 ms 23936 KB Output is correct
13 Correct 16 ms 23936 KB Output is correct
14 Correct 17 ms 23936 KB Output is correct
15 Correct 17 ms 23936 KB Output is correct
16 Correct 17 ms 23808 KB Output is correct
17 Correct 17 ms 23936 KB Output is correct
18 Correct 16 ms 23936 KB Output is correct
19 Correct 17 ms 23936 KB Output is correct
20 Correct 17 ms 23928 KB Output is correct
21 Correct 17 ms 23936 KB Output is correct
22 Correct 17 ms 23808 KB Output is correct

Subtask #4
35.0 / 35.0

# Verdict Execution time Memory Grader output
1 Correct 15 ms 23808 KB Output is correct
2 Correct 17 ms 23808 KB Output is correct
3 Correct 15 ms 23808 KB Output is correct
4 Correct 17 ms 23808 KB Output is correct
5 Correct 15 ms 23808 KB Output is correct
6 Correct 19 ms 23808 KB Output is correct
7 Correct 17 ms 23808 KB Output is correct
8 Correct 15 ms 23808 KB Output is correct
9 Correct 14 ms 23808 KB Output is correct
10 Correct 14 ms 23788 KB Output is correct
11 Correct 483 ms 63992 KB Output is correct
12 Correct 406 ms 60068 KB Output is correct
13 Correct 1422 ms 65036 KB Output is correct
14 Correct 487 ms 45108 KB Output is correct
15 Correct 1066 ms 65196 KB Output is correct
16 Correct 1246 ms 65484 KB Output is correct
17 Correct 21 ms 23884 KB Output is correct
18 Correct 15 ms 23936 KB Output is correct
19 Correct 16 ms 23936 KB Output is correct
20 Correct 17 ms 23936 KB Output is correct
21 Correct 17 ms 23936 KB Output is correct
22 Correct 17 ms 23808 KB Output is correct
23 Correct 17 ms 23936 KB Output is correct
24 Correct 16 ms 23936 KB Output is correct
25 Correct 17 ms 23936 KB Output is correct
26 Correct 17 ms 23928 KB Output is correct
27 Correct 17 ms 23936 KB Output is correct
28 Correct 17 ms 23808 KB Output is correct
29 Correct 16 ms 23808 KB Output is correct
30 Correct 450 ms 63864 KB Output is correct
31 Correct 457 ms 63880 KB Output is correct
32 Correct 442 ms 111108 KB Output is correct
33 Correct 520 ms 188792 KB Output is correct
34 Correct 1064 ms 64760 KB Output is correct
35 Correct 1075 ms 64760 KB Output is correct
36 Correct 1012 ms 71652 KB Output is correct
37 Correct 1493 ms 71532 KB Output is correct
38 Correct 724 ms 73200 KB Output is correct
39 Correct 766 ms 73332 KB Output is correct
40 Correct 1079 ms 73196 KB Output is correct