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답안 #1028577

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
1028577 2024-07-20T05:22:13 Z Thanhs Mousetrap (CEOI17_mousetrap) C++14
100 / 100
 542 ms 194004 KB 
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>
using namespace std;
// #define int long long
// #define double long double
 
#define endl '\n'
#define fastIO ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);
#define setmin(x, y) x = min((x), (y))
#define setmax(x, y) x = max((x), (y))
#define sqr(x) ((x) * (x))
#define fi first
#define se second
 
// mt19937 hdp(chrono::high_resolution_clock::now().time_since_epoch().count());
// int rand(int l, int r){return l + ((hdp() % (r - l + 1)) + r - l + 1) % (r - l + 1);}
 
const int NM = 1e6 + 5;
const int mod = 1e6 + 3;
const int inf = 1e9 + 1;

vector<int> g[NM];
int n, t, m, w[NM], W[NM], dep[NM], par[NM];
vector<pair<int, int>> L;

void dfs(int u = t, int p = 0)
{
    if (u != t)
        W[u] = W[par[u]] + max(0, (int)g[u].size() - 2);
    int be = 0, sb = 0;
    for (auto v : g[u])
    {
        if (v == p)
            continue;
        dep[v] = dep[u] + 1;
        par[v] = u;
        dfs(v, u);
        if (be < w[v])
        {
            sb = be;
            be = w[v];
        }
        else if (sb < w[v])
            sb = w[v];
    }
    if (g[u].size() - !!p == 0)
        w[u] = 0;
    else if (g[u].size() - !!p == 1)
        w[u] = 1;
    else 
        w[u] += sb + g[u].size() - !!p;
}

bool check(int x)
{
    int B = 0;
    for (auto p : L)
        if (p.se + B > x)
        {
            if (B > p.fi)
                return false;
            B++;
        }
    if (B > x)
        return false;
    return true;
}

signed main()
{
    if (fopen("in.txt", "r")) {
        freopen("in.txt", "r", stdin);
        freopen("out.txt", "w", stdout);
    }
    fastIO
    cin >> n >> t >> m;
    for (int i = 2; i <= n; i++)
    {
        int u, v;
        cin >> u >> v;
        g[u].push_back(v);
        g[v].push_back(u);
    }
    dfs();
    int u = m, prv = 0;
    while (u != t)
    {
        for (auto v : g[u])
            if (v != prv && v != par[u])
                L.emplace_back(dep[m] - dep[u], w[v] + W[par[v]] + 1 - !!prv);
        prv = u;
        u = par[u];
    }
    // for (auto t : L)
    //     cout << t.fi << ' ' << t.se << endl;
    sort(L.begin(), L.end());
    int l = -1, r = 2 * n;
    while (l < r - 1)
    {
        int mid = l + r >> 1;
        if (check(mid))
            r = mid;
        else
            l = mid;
    }
    cout << r;
}

Compilation message

mousetrap.cpp: In function 'int main()':
mousetrap.cpp:101:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  101 |         int mid = l + r >> 1;
      |                   ~~^~~
mousetrap.cpp:73:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   73 |         freopen("in.txt", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
mousetrap.cpp:74:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   74 |         freopen("out.txt", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
20.0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 12 ms 23900 KB Output is correct
2 Correct 15 ms 23896 KB Output is correct
3 Correct 12 ms 23900 KB Output is correct
4 Correct 12 ms 23900 KB Output is correct
5 Correct 12 ms 23760 KB Output is correct
6 Correct 12 ms 23900 KB Output is correct
7 Correct 14 ms 23900 KB Output is correct
8 Correct 12 ms 23976 KB Output is correct
9 Correct 12 ms 23900 KB Output is correct
10 Correct 12 ms 23952 KB Output is correct

Subtask #2
25.0 / 25.0

# 결과 실행 시간 메모리 Grader output
1 Correct 184 ms 81228 KB Output is correct
2 Correct 161 ms 75376 KB Output is correct
3 Correct 542 ms 82184 KB Output is correct
4 Correct 219 ms 53332 KB Output is correct
5 Correct 492 ms 82164 KB Output is correct
6 Correct 514 ms 82152 KB Output is correct

Subtask #3
20.0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 12 ms 23900 KB Output is correct
2 Correct 15 ms 23896 KB Output is correct
3 Correct 12 ms 23900 KB Output is correct
4 Correct 12 ms 23900 KB Output is correct
5 Correct 12 ms 23760 KB Output is correct
6 Correct 12 ms 23900 KB Output is correct
7 Correct 14 ms 23900 KB Output is correct
8 Correct 12 ms 23976 KB Output is correct
9 Correct 12 ms 23900 KB Output is correct
10 Correct 12 ms 23952 KB Output is correct
11 Correct 12 ms 23896 KB Output is correct
12 Correct 12 ms 23900 KB Output is correct
13 Correct 12 ms 23900 KB Output is correct
14 Correct 12 ms 23976 KB Output is correct
15 Correct 13 ms 23900 KB Output is correct
16 Correct 12 ms 23900 KB Output is correct
17 Correct 14 ms 23884 KB Output is correct
18 Correct 12 ms 23896 KB Output is correct
19 Correct 12 ms 23900 KB Output is correct
20 Correct 12 ms 23900 KB Output is correct
21 Correct 16 ms 23884 KB Output is correct
22 Correct 12 ms 23900 KB Output is correct

Subtask #4
35.0 / 35.0

# 결과 실행 시간 메모리 Grader output
1 Correct 12 ms 23900 KB Output is correct
2 Correct 15 ms 23896 KB Output is correct
3 Correct 12 ms 23900 KB Output is correct
4 Correct 12 ms 23900 KB Output is correct
5 Correct 12 ms 23760 KB Output is correct
6 Correct 12 ms 23900 KB Output is correct
7 Correct 14 ms 23900 KB Output is correct
8 Correct 12 ms 23976 KB Output is correct
9 Correct 12 ms 23900 KB Output is correct
10 Correct 12 ms 23952 KB Output is correct
11 Correct 184 ms 81228 KB Output is correct
12 Correct 161 ms 75376 KB Output is correct
13 Correct 542 ms 82184 KB Output is correct
14 Correct 219 ms 53332 KB Output is correct
15 Correct 492 ms 82164 KB Output is correct
16 Correct 514 ms 82152 KB Output is correct
17 Correct 12 ms 23896 KB Output is correct
18 Correct 12 ms 23900 KB Output is correct
19 Correct 12 ms 23900 KB Output is correct
20 Correct 12 ms 23976 KB Output is correct
21 Correct 13 ms 23900 KB Output is correct
22 Correct 12 ms 23900 KB Output is correct
23 Correct 14 ms 23884 KB Output is correct
24 Correct 12 ms 23896 KB Output is correct
25 Correct 12 ms 23900 KB Output is correct
26 Correct 12 ms 23900 KB Output is correct
27 Correct 16 ms 23884 KB Output is correct
28 Correct 12 ms 23900 KB Output is correct
29 Correct 12 ms 23900 KB Output is correct
30 Correct 217 ms 83992 KB Output is correct
31 Correct 186 ms 84308 KB Output is correct
32 Correct 331 ms 194004 KB Output is correct
33 Correct 304 ms 193876 KB Output is correct
34 Correct 503 ms 85116 KB Output is correct
35 Correct 496 ms 85072 KB Output is correct
36 Correct 510 ms 98084 KB Output is correct
37 Correct 511 ms 98136 KB Output is correct
38 Correct 348 ms 99880 KB Output is correct
39 Correct 363 ms 100048 KB Output is correct
40 Correct 352 ms 100040 KB Output is correct