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Submission #256189

# Submission time Handle Problem Language Result Execution time Memory
256189 2020-08-02T11:12:25 Z giorgikob Mousetrap (CEOI17_mousetrap) C++14
100 / 100
 1317 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.tie(0); cout.tie(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 16 ms 23808 KB Output is correct
2 Correct 14 ms 23808 KB Output is correct
3 Correct 15 ms 23808 KB Output is correct
4 Correct 14 ms 23808 KB Output is correct
5 Correct 15 ms 23808 KB Output is correct
6 Correct 17 ms 23808 KB Output is correct
7 Correct 16 ms 23784 KB Output is correct
8 Correct 16 ms 23808 KB Output is correct
9 Correct 22 ms 23808 KB Output is correct
10 Correct 15 ms 23808 KB Output is correct

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 437 ms 65660 KB Output is correct
2 Correct 399 ms 61528 KB Output is correct
3 Correct 1056 ms 66608 KB Output is correct
4 Correct 510 ms 46712 KB Output is correct
5 Correct 1186 ms 66708 KB Output is correct
6 Correct 1285 ms 65912 KB Output is correct

Subtask #3
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 16 ms 23808 KB Output is correct
2 Correct 14 ms 23808 KB Output is correct
3 Correct 15 ms 23808 KB Output is correct
4 Correct 14 ms 23808 KB Output is correct
5 Correct 15 ms 23808 KB Output is correct
6 Correct 17 ms 23808 KB Output is correct
7 Correct 16 ms 23784 KB Output is correct
8 Correct 16 ms 23808 KB Output is correct
9 Correct 22 ms 23808 KB Output is correct
10 Correct 15 ms 23808 KB Output is correct
11 Correct 17 ms 23808 KB Output is correct
12 Correct 15 ms 23936 KB Output is correct
13 Correct 19 ms 23936 KB Output is correct
14 Correct 18 ms 23936 KB Output is correct
15 Correct 20 ms 23936 KB Output is correct
16 Correct 15 ms 23936 KB Output is correct
17 Correct 17 ms 23936 KB Output is correct
18 Correct 16 ms 23936 KB Output is correct
19 Correct 15 ms 23936 KB Output is correct
20 Correct 15 ms 23936 KB Output is correct
21 Correct 15 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 16 ms 23808 KB Output is correct
2 Correct 14 ms 23808 KB Output is correct
3 Correct 15 ms 23808 KB Output is correct
4 Correct 14 ms 23808 KB Output is correct
5 Correct 15 ms 23808 KB Output is correct
6 Correct 17 ms 23808 KB Output is correct
7 Correct 16 ms 23784 KB Output is correct
8 Correct 16 ms 23808 KB Output is correct
9 Correct 22 ms 23808 KB Output is correct
10 Correct 15 ms 23808 KB Output is correct
11 Correct 437 ms 65660 KB Output is correct
12 Correct 399 ms 61528 KB Output is correct
13 Correct 1056 ms 66608 KB Output is correct
14 Correct 510 ms 46712 KB Output is correct
15 Correct 1186 ms 66708 KB Output is correct
16 Correct 1285 ms 65912 KB Output is correct
17 Correct 17 ms 23808 KB Output is correct
18 Correct 15 ms 23936 KB Output is correct
19 Correct 19 ms 23936 KB Output is correct
20 Correct 18 ms 23936 KB Output is correct
21 Correct 20 ms 23936 KB Output is correct
22 Correct 15 ms 23936 KB Output is correct
23 Correct 17 ms 23936 KB Output is correct
24 Correct 16 ms 23936 KB Output is correct
25 Correct 15 ms 23936 KB Output is correct
26 Correct 15 ms 23936 KB Output is correct
27 Correct 15 ms 23936 KB Output is correct
28 Correct 17 ms 23808 KB Output is correct
29 Correct 15 ms 23872 KB Output is correct
30 Correct 438 ms 63480 KB Output is correct
31 Correct 441 ms 63608 KB Output is correct
32 Correct 435 ms 110824 KB Output is correct
33 Correct 556 ms 188792 KB Output is correct
34 Correct 1317 ms 64632 KB Output is correct
35 Correct 1292 ms 64760 KB Output is correct
36 Correct 1236 ms 71400 KB Output is correct
37 Correct 1166 ms 71660 KB Output is correct
38 Correct 795 ms 73072 KB Output is correct
39 Correct 765 ms 73200 KB Output is correct
40 Correct 693 ms 73196 KB Output is correct