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답안 #256190

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
256190 2020-08-02T11:13:06 Z giorgikob Mousetrap (CEOI17_mousetrap) C++14
100 / 100
 1401 ms 188220 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;
                scanf("%d%d",&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:88:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int i = 0; i < path.size(); i++){
                        ~~^~~~~~~~~~~~~
mousetrap.cpp:91:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
                 if(i == path.size() - 1) k--;
                    ~~^~~~~~~~~~~~~~~~~~
mousetrap.cpp:96:44: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
                         if(path.size() - 1 != i && to == path[i+1]) continue;
                            ~~~~~~~~~~~~~~~~^~~~
mousetrap.cpp:73:22: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
                 scanf("%d%d",&x,&y);
                 ~~~~~^~~~~~~~~~~~~~

Subtask #1
20.0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 17 ms 23808 KB Output is correct
2 Correct 14 ms 23808 KB Output is correct
3 Correct 20 ms 23808 KB Output is correct
4 Correct 19 ms 23808 KB Output is correct
5 Correct 14 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 18 ms 23808 KB Output is correct
10 Correct 15 ms 23808 KB Output is correct

Subtask #2
25.0 / 25.0

# 결과 실행 시간 메모리 Grader output
1 Correct 489 ms 62968 KB Output is correct
2 Correct 435 ms 59000 KB Output is correct
3 Correct 1081 ms 64248 KB Output is correct
4 Correct 498 ms 44024 KB Output is correct
5 Correct 1075 ms 64088 KB Output is correct
6 Correct 1108 ms 64248 KB Output is correct

Subtask #3
20.0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 17 ms 23808 KB Output is correct
2 Correct 14 ms 23808 KB Output is correct
3 Correct 20 ms 23808 KB Output is correct
4 Correct 19 ms 23808 KB Output is correct
5 Correct 14 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 18 ms 23808 KB Output is correct
10 Correct 15 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 16 ms 23936 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 23808 KB Output is correct
21 Correct 16 ms 23808 KB Output is correct
22 Correct 15 ms 23808 KB Output is correct

Subtask #4
35.0 / 35.0

# 결과 실행 시간 메모리 Grader output
1 Correct 17 ms 23808 KB Output is correct
2 Correct 14 ms 23808 KB Output is correct
3 Correct 20 ms 23808 KB Output is correct
4 Correct 19 ms 23808 KB Output is correct
5 Correct 14 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 18 ms 23808 KB Output is correct
10 Correct 15 ms 23808 KB Output is correct
11 Correct 489 ms 62968 KB Output is correct
12 Correct 435 ms 59000 KB Output is correct
13 Correct 1081 ms 64248 KB Output is correct
14 Correct 498 ms 44024 KB Output is correct
15 Correct 1075 ms 64088 KB Output is correct
16 Correct 1108 ms 64248 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 16 ms 23936 KB Output is correct
23 Correct 15 ms 23808 KB Output is correct
24 Correct 15 ms 23808 KB Output is correct
25 Correct 15 ms 23808 KB Output is correct
26 Correct 15 ms 23808 KB Output is correct
27 Correct 16 ms 23808 KB Output is correct
28 Correct 15 ms 23808 KB Output is correct
29 Correct 24 ms 23808 KB Output is correct
30 Correct 488 ms 62896 KB Output is correct
31 Correct 469 ms 62968 KB Output is correct
32 Correct 474 ms 110188 KB Output is correct
33 Correct 564 ms 188220 KB Output is correct
34 Correct 1389 ms 63992 KB Output is correct
35 Correct 1401 ms 63992 KB Output is correct
36 Correct 1076 ms 70936 KB Output is correct
37 Correct 1284 ms 70892 KB Output is correct
38 Correct 822 ms 72708 KB Output is correct
39 Correct 753 ms 72556 KB Output is correct
40 Correct 825 ms 72692 KB Output is correct