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Submission #289094

# Submission time Handle Problem Language Result Execution time Memory
289094 2020-09-02T10:48:05 Z evpipis Mousetrap (CEOI17_mousetrap) C++11
65 / 100
 5000 ms 188384 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(){
    //freopen("trap.01.05.in", "r", stdin);

    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++;
        cost[i].pb(0);

        /*printf("i = %d\n", i);
        for (int j = 0; j < cost[i].size(); j++)
            printf("%d ", cost[i][j]);
        printf("\n");*/
    }

    for (int i = (int)order.size()-1; i >= 0; i--){
        for (int rem = 1; rem <= i+1; rem++){
            //printf("computing dp: i = %d, rem = %d\n", i, rem);

            dp[i&1][rem] = inf;

            int opt = -1;
            for (int j = 0; j < cost[i].size() && j <= rem; j++){
                if (cost[i][j] >= dp[(i+1)&1][rem-j+1])
                    opt = j;

                //dp[i&1][rem] = min(dp[i&1][rem], j+max(cost[i][j], dp[(i+1)&1][rem-j+1]));
            }

            //printf("opt = %d\n", opt);

            if (opt != -1)
                dp[i&1][rem] = min(dp[i&1][rem], opt + cost[i][opt]);
            if (opt+1 < cost[i].size() && opt+1 <= rem)
                dp[i&1][rem] = min(dp[i&1][rem], opt+1 + dp[(i+1)&1][rem-opt]);
        }

        //printf("i = %d\n", i);
        //for (int rem = 1; rem <= i+1; rem++)
          //  printf("rem = %d, dp = %d\n", rem, dp[i&1][rem]);
    }

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

Compilation message

mousetrap.cpp: In function 'int main()':
mousetrap.cpp:98:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   98 |             for (int j = 0; j < cost[i].size() && j <= rem; j++){
      |                             ~~^~~~~~~~~~~~~~~~
mousetrap.cpp:109:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  109 |             if (opt+1 < cost[i].size() && opt+1 <= rem)
      |                 ~~~~~~^~~~~~~~~~~~~~~~
mousetrap.cpp:54:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   54 |     scanf("%d %d %d", &n, &en, &st);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
mousetrap.cpp:57:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   57 |         scanf("%d %d", &a, &b);
      |         ~~~~~^~~~~~~~~~~~~~~~~

Subtask #1
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 32 ms 47352 KB Output is correct
2 Correct 32 ms 47356 KB Output is correct
3 Correct 33 ms 47352 KB Output is correct
4 Correct 32 ms 47360 KB Output is correct
5 Correct 33 ms 47360 KB Output is correct
6 Correct 32 ms 47480 KB Output is correct
7 Correct 32 ms 47360 KB Output is correct
8 Correct 32 ms 47488 KB Output is correct
9 Correct 32 ms 47480 KB Output is correct
10 Correct 33 ms 47360 KB Output is correct

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 429 ms 78592 KB Output is correct
2 Correct 394 ms 75468 KB Output is correct
3 Correct 884 ms 79736 KB Output is correct
4 Correct 430 ms 63608 KB Output is correct
5 Correct 879 ms 79736 KB Output is correct
6 Correct 888 ms 79736 KB Output is correct

Subtask #3
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 32 ms 47352 KB Output is correct
2 Correct 32 ms 47356 KB Output is correct
3 Correct 33 ms 47352 KB Output is correct
4 Correct 32 ms 47360 KB Output is correct
5 Correct 33 ms 47360 KB Output is correct
6 Correct 32 ms 47480 KB Output is correct
7 Correct 32 ms 47360 KB Output is correct
8 Correct 32 ms 47488 KB Output is correct
9 Correct 32 ms 47480 KB Output is correct
10 Correct 33 ms 47360 KB Output is correct
11 Correct 32 ms 47360 KB Output is correct
12 Correct 32 ms 47360 KB Output is correct
13 Correct 33 ms 47352 KB Output is correct
14 Correct 35 ms 47480 KB Output is correct
15 Correct 35 ms 47480 KB Output is correct
16 Correct 32 ms 47332 KB Output is correct
17 Correct 33 ms 47352 KB Output is correct
18 Correct 33 ms 47356 KB Output is correct
19 Correct 33 ms 47352 KB Output is correct
20 Correct 32 ms 47360 KB Output is correct
21 Correct 33 ms 47352 KB Output is correct
22 Correct 32 ms 47360 KB Output is correct

Subtask #4
0 / 35.0

# Verdict Execution time Memory Grader output
1 Correct 32 ms 47352 KB Output is correct
2 Correct 32 ms 47356 KB Output is correct
3 Correct 33 ms 47352 KB Output is correct
4 Correct 32 ms 47360 KB Output is correct
5 Correct 33 ms 47360 KB Output is correct
6 Correct 32 ms 47480 KB Output is correct
7 Correct 32 ms 47360 KB Output is correct
8 Correct 32 ms 47488 KB Output is correct
9 Correct 32 ms 47480 KB Output is correct
10 Correct 33 ms 47360 KB Output is correct
11 Correct 429 ms 78592 KB Output is correct
12 Correct 394 ms 75468 KB Output is correct
13 Correct 884 ms 79736 KB Output is correct
14 Correct 430 ms 63608 KB Output is correct
15 Correct 879 ms 79736 KB Output is correct
16 Correct 888 ms 79736 KB Output is correct
17 Correct 32 ms 47360 KB Output is correct
18 Correct 32 ms 47360 KB Output is correct
19 Correct 33 ms 47352 KB Output is correct
20 Correct 35 ms 47480 KB Output is correct
21 Correct 35 ms 47480 KB Output is correct
22 Correct 32 ms 47332 KB Output is correct
23 Correct 33 ms 47352 KB Output is correct
24 Correct 33 ms 47356 KB Output is correct
25 Correct 33 ms 47352 KB Output is correct
26 Correct 32 ms 47360 KB Output is correct
27 Correct 33 ms 47352 KB Output is correct
28 Correct 32 ms 47360 KB Output is correct
29 Correct 32 ms 47352 KB Output is correct
30 Correct 447 ms 78840 KB Output is correct
31 Correct 433 ms 78840 KB Output is correct
32 Execution timed out 5068 ms 188384 KB Time limit exceeded
33 Halted 0 ms 0 KB -