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Submission #256186

# Submission time Handle Problem Language Result Execution time Memory
256186 2020-08-02T11:10:33 Z giorgikob Mousetrap (CEOI17_mousetrap) C++14
100 / 100
 1991 ms 201848 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(){

        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:86:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int i = 0; i < path.size(); i++){
                        ~~^~~~~~~~~~~~~
mousetrap.cpp:89:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
                 if(i == path.size() - 1) k--;
                    ~~^~~~~~~~~~~~~~~~~~
mousetrap.cpp:94:44: 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 17 ms 23808 KB Output is correct
2 Correct 14 ms 23808 KB Output is correct
3 Correct 17 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 17 ms 23808 KB Output is correct
7 Correct 14 ms 23808 KB Output is correct
8 Correct 17 ms 23808 KB Output is correct
9 Correct 15 ms 23808 KB Output is correct
10 Correct 18 ms 23808 KB Output is correct

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 1173 ms 63792 KB Output is correct
2 Correct 1000 ms 59640 KB Output is correct
3 Correct 1743 ms 64680 KB Output is correct
4 Correct 864 ms 44664 KB Output is correct
5 Correct 1908 ms 64888 KB Output is correct
6 Correct 1751 ms 65012 KB Output is correct

Subtask #3
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 17 ms 23808 KB Output is correct
2 Correct 14 ms 23808 KB Output is correct
3 Correct 17 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 17 ms 23808 KB Output is correct
7 Correct 14 ms 23808 KB Output is correct
8 Correct 17 ms 23808 KB Output is correct
9 Correct 15 ms 23808 KB Output is correct
10 Correct 18 ms 23808 KB Output is correct
11 Correct 15 ms 23808 KB Output is correct
12 Correct 15 ms 23808 KB Output is correct
13 Correct 15 ms 23808 KB Output is correct
14 Correct 15 ms 23936 KB Output is correct
15 Correct 15 ms 23936 KB Output is correct
16 Correct 15 ms 23808 KB Output is correct
17 Correct 16 ms 23808 KB Output is correct
18 Correct 18 ms 23808 KB Output is correct
19 Correct 17 ms 23808 KB Output is correct
20 Correct 18 ms 23808 KB Output is correct
21 Correct 18 ms 23808 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 17 ms 23808 KB Output is correct
2 Correct 14 ms 23808 KB Output is correct
3 Correct 17 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 17 ms 23808 KB Output is correct
7 Correct 14 ms 23808 KB Output is correct
8 Correct 17 ms 23808 KB Output is correct
9 Correct 15 ms 23808 KB Output is correct
10 Correct 18 ms 23808 KB Output is correct
11 Correct 1173 ms 63792 KB Output is correct
12 Correct 1000 ms 59640 KB Output is correct
13 Correct 1743 ms 64680 KB Output is correct
14 Correct 864 ms 44664 KB Output is correct
15 Correct 1908 ms 64888 KB Output is correct
16 Correct 1751 ms 65012 KB Output is correct
17 Correct 15 ms 23808 KB Output is correct
18 Correct 15 ms 23808 KB Output is correct
19 Correct 15 ms 23808 KB Output is correct
20 Correct 15 ms 23936 KB Output is correct
21 Correct 15 ms 23936 KB Output is correct
22 Correct 15 ms 23808 KB Output is correct
23 Correct 16 ms 23808 KB Output is correct
24 Correct 18 ms 23808 KB Output is correct
25 Correct 17 ms 23808 KB Output is correct
26 Correct 18 ms 23808 KB Output is correct
27 Correct 18 ms 23808 KB Output is correct
28 Correct 17 ms 23808 KB Output is correct
29 Correct 15 ms 23936 KB Output is correct
30 Correct 1090 ms 76536 KB Output is correct
31 Correct 1114 ms 76428 KB Output is correct
32 Correct 1108 ms 123884 KB Output is correct
33 Correct 1180 ms 201848 KB Output is correct
34 Correct 1718 ms 77248 KB Output is correct
35 Correct 1991 ms 77280 KB Output is correct
36 Correct 1671 ms 84268 KB Output is correct
37 Correct 1693 ms 84180 KB Output is correct
38 Correct 1394 ms 85908 KB Output is correct
39 Correct 1583 ms 85904 KB Output is correct
40 Correct 1395 ms 86124 KB Output is correct