oj.uz

Submission #288972

# Submission time Handle Problem Language Result Execution time Memory
288972 2020-09-02T08:51:17 Z evpipis Mousetrap (CEOI17_mousetrap) C++11
65 / 100
 5000 ms 170468 KB 
#include <bits/stdc++.h>
using namespace std;

#define fi first
#define se second
#define mp make_pair
#define pb push_back
typedef pair<int, int> ii;

const int len = 1e6+5, inf = 1e9;
vector<int> adj[len], cost[len], order;
int block[len], dp[2][len];

int fix_order(int u, int p, int en){
    if (u == en){
        block[u] = 1;
        return 1;
    }

    for (auto v: adj[u]){
        if (v == p) continue;

        if (fix_order(v, u, en)){
            order.pb(u);
            block[u] = 1;
            return 1;
        }
    }

    return 0;
}

int run_dfs(int u, int p){
    int mx1 = 0, mx2 = 0, kids = 0;
    for (auto v: adj[u]){
        if (v == p) continue;

        kids++;

        int cur = run_dfs(v, u);
        if (cur > mx1)
            mx2 = mx1, mx1 = cur;
        else if (cur > mx2)
            mx2 = cur;
    }

    return mx2+kids;
}

int main(){
    int n, en, st;
    scanf("%d %d %d", &n, &en, &st);
    for (int i = 0; i < n-1; i++){
        int a, b;
        scanf("%d %d", &a, &b);
        adj[a].pb(b);
        adj[b].pb(a);
    }


    fix_order(st, st, en);
    reverse(order.begin(), order.end());

    for (int i = (int)order.size()-1, cnt = 0; i >= 0; i--){
        int u = order[i];

        //printf("i = %d, u = %d\n", i, u);
        for (auto v: adj[u]){
            if (block[v]) continue;

            cost[i].pb(run_dfs(v, u)+1);

            //printf("%d -> %d, cost = %d\n", u, v, cost[i].back());
        }

        sort(cost[i].begin(), cost[i].end());
        reverse(cost[i].begin(), cost[i].end());

        for (int j = (int)cost[i].size()-1; j >= 0; j--)
            cost[i][j] += cnt++;
    }

    for (int i = (int)order.size()-1; i >= 0; i--){
        for (int rem = 1; rem <= i+1; rem++){
            dp[i&1][rem] = inf;
            if (rem >= cost[i].size())
                dp[i&1][rem] = cost[i].size() + dp[(i+1)&1][rem-cost[i].size()+1];
            for (int j = 0; j < cost[i].size(); j++){
                if (j <= rem)
                    dp[i&1][rem] = min(dp[i&1][rem], j+max(cost[i][j], dp[(i+1)&1][rem-j+1]));
            }
        }
    }

    printf("%d\n", dp[0][1]);
    return 0;
}

Compilation message

mousetrap.cpp: In function 'int main()':
mousetrap.cpp:86:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   86 |             if (rem >= cost[i].size())
      |                 ~~~~^~~~~~~~~~~~~~~~~
mousetrap.cpp:88:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   88 |             for (int j = 0; j < cost[i].size(); j++){
      |                             ~~^~~~~~~~~~~~~~~~
mousetrap.cpp:52:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   52 |     scanf("%d %d %d", &n, &en, &st);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
mousetrap.cpp:55:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   55 |         scanf("%d %d", &a, &b);
      |         ~~~~~^~~~~~~~~~~~~~~~~

Subtask #1
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 29 ms 47352 KB Output is correct
2 Correct 28 ms 47356 KB Output is correct
3 Correct 29 ms 47360 KB Output is correct
4 Correct 28 ms 47352 KB Output is correct
5 Correct 29 ms 47360 KB Output is correct
6 Correct 28 ms 47352 KB Output is correct
7 Correct 28 ms 47360 KB Output is correct
8 Correct 29 ms 47360 KB Output is correct
9 Correct 29 ms 47360 KB Output is correct
10 Correct 28 ms 47360 KB Output is correct

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 420 ms 92024 KB Output is correct
2 Correct 377 ms 87416 KB Output is correct
3 Correct 882 ms 92976 KB Output is correct
4 Correct 415 ms 69880 KB Output is correct
5 Correct 876 ms 93048 KB Output is correct
6 Correct 880 ms 93048 KB Output is correct

Subtask #3
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 29 ms 47352 KB Output is correct
2 Correct 28 ms 47356 KB Output is correct
3 Correct 29 ms 47360 KB Output is correct
4 Correct 28 ms 47352 KB Output is correct
5 Correct 29 ms 47360 KB Output is correct
6 Correct 28 ms 47352 KB Output is correct
7 Correct 28 ms 47360 KB Output is correct
8 Correct 29 ms 47360 KB Output is correct
9 Correct 29 ms 47360 KB Output is correct
10 Correct 28 ms 47360 KB Output is correct
11 Correct 29 ms 47360 KB Output is correct
12 Correct 28 ms 47360 KB Output is correct
13 Correct 30 ms 47352 KB Output is correct
14 Correct 30 ms 47352 KB Output is correct
15 Correct 29 ms 47360 KB Output is correct
16 Correct 31 ms 47352 KB Output is correct
17 Correct 28 ms 47360 KB Output is correct
18 Correct 29 ms 47360 KB Output is correct
19 Correct 29 ms 47360 KB Output is correct
20 Correct 29 ms 47360 KB Output is correct
21 Correct 29 ms 47356 KB Output is correct
22 Correct 28 ms 47360 KB Output is correct

Subtask #4
0 / 35.0

# Verdict Execution time Memory Grader output
1 Correct 29 ms 47352 KB Output is correct
2 Correct 28 ms 47356 KB Output is correct
3 Correct 29 ms 47360 KB Output is correct
4 Correct 28 ms 47352 KB Output is correct
5 Correct 29 ms 47360 KB Output is correct
6 Correct 28 ms 47352 KB Output is correct
7 Correct 28 ms 47360 KB Output is correct
8 Correct 29 ms 47360 KB Output is correct
9 Correct 29 ms 47360 KB Output is correct
10 Correct 28 ms 47360 KB Output is correct
11 Correct 420 ms 92024 KB Output is correct
12 Correct 377 ms 87416 KB Output is correct
13 Correct 882 ms 92976 KB Output is correct
14 Correct 415 ms 69880 KB Output is correct
15 Correct 876 ms 93048 KB Output is correct
16 Correct 880 ms 93048 KB Output is correct
17 Correct 29 ms 47360 KB Output is correct
18 Correct 28 ms 47360 KB Output is correct
19 Correct 30 ms 47352 KB Output is correct
20 Correct 30 ms 47352 KB Output is correct
21 Correct 29 ms 47360 KB Output is correct
22 Correct 31 ms 47352 KB Output is correct
23 Correct 28 ms 47360 KB Output is correct
24 Correct 29 ms 47360 KB Output is correct
25 Correct 29 ms 47360 KB Output is correct
26 Correct 29 ms 47360 KB Output is correct
27 Correct 29 ms 47356 KB Output is correct
28 Correct 28 ms 47360 KB Output is correct
29 Correct 30 ms 47360 KB Output is correct
30 Correct 436 ms 91976 KB Output is correct
31 Correct 431 ms 92036 KB Output is correct
32 Execution timed out 5062 ms 170468 KB Time limit exceeded
33 Halted 0 ms 0 KB -