oj.uz

Submission #47084

# Submission time Handle Problem Language Result Execution time Memory
47084 2018-04-27T10:20:13 Z qoo2p5 Mousetrap (CEOI17_mousetrap) C++17
100 / 100
 1190 ms 230704 KB 
#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef long double ld;

const int INF = (int) 1e9 + 1e6;
const ll LINF = (ll) 1e18 + 1e9;
const ll MOD = (ll) 1e9 + 7;

#define sz(x) (int) (x).size()
#define mp(x, y) make_pair(x, y)
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define lb(s, t, x) (int) (lower_bound(s, t, x) - s)
#define ub(s, t, x) (int) (upper_bound(s, t, x) - s)
#define rep(i, f, t) for (auto i = f; i < t; ++(i))
#define per(i, f, t) for (auto i = (f); i >= (t); --(i))

ll power(ll x, ll y, ll mod = MOD) {
    if (y == 0) {
        return 1;
    }
    if (y & 1) {
        return power(x, y - 1, mod) * x % mod;
    } else {
        ll tmp = power(x, y / 2, mod);
        return tmp * tmp % mod;
    }
}

template<typename A, typename B> bool mini(A &x, const B &y) {
    if (y < x) {
        x = y;
        return true;
    }
    return false;
}

template<typename A, typename B> bool maxi(A &x, const B &y) {
    if (x < y) {
        x = y;
        return true;
    }
    return false;
}

void add(ll &x, ll y) {
    x += y;
    if (x >= MOD) x -= MOD;
    if (x < 0) x += MOD;
}

void run();

#define TASK ""

int main() {
#ifdef LOCAL
    if (strlen(TASK) > 0) {
        cerr << "Reminder: you are using file i/o, filename: " TASK "!" << endl << endl;
    }
#endif
#ifndef LOCAL
    if (strlen(TASK)) {
        freopen(TASK ".in", "r", stdin);
        freopen(TASK ".out", "w", stdout);
    }
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
#endif
    cout << fixed << setprecision(12);
    run();
    return 0;
}

// == SOLUTION == //

const int N = (int) 1e6 + 123;

int n, t, m;
vector<int> g[N];
int p[N];
int cost[N];
int up[N];

void calc(int v, int p = -1) {
    ::p[v] = p;
    int ptr = 0;
    int pos = -1;
    
    for (int u : g[v]) {
        if (u == p) {
            pos = ptr;
            continue;
        }
        
        up[u] = up[v];
        if (v != t) {
            up[u] += sz(g[v]) - 2;
        }
        calc(u, v);
        ptr++;
    }
    
    if (pos != -1) {
        g[v].erase(g[v].begin() + pos);
    }
    
    if (sz(g[v]) == 0) {
        cost[v] = 0;
    } else if (sz(g[v]) == 1) {
        cost[v] = 1;
    } else {
        vector<int> q;
        for (int u : g[v]) {
            q.push_back(cost[u]);
        }
        sort(all(q));
        cost[v] = sz(g[v]) + q[sz(q) - 2];
    }
}

void run() {
    cin >> n >> t >> m;
    rep(i, 0, n - 1) {
        int u, v;
        cin >> u >> v;
        g[u].pb(v);
        g[v].pb(u);
    }
    
    calc(t);
    vector<pair<int, int>> wow;
    int prv = -1;
    int w = m;
    int dist = 0;
    while (w != t) {
        for (int u : g[w]) {
            if (u == prv) {
                continue;
            }
            wow.pb({dist + 1, cost[u] + up[u] + (dist == 0)});
        }
        prv = w;
        w = p[w];
        dist++;
    }
    
    sort(all(wow));
    
    int left = -1;
    int right = n;
    while (right - left > 1) {
        int mid = (left + right) / 2;
        bool ok = 1;
        int cnt = 0;
        rep(i, 0, sz(wow)) {
            int j = i;
            while (j + 1 < sz(wow) && wow[j + 1].first == wow[j].first) {
                j++;
            }
            int ncnt = cnt;
            
            rep(k, i, j + 1) {
                auto it = wow[k];
                if (it.second + cnt <= mid) {
                    continue;
                }
                if (ncnt >= it.first) {
                    ok = 0;
                    break;
                }
                ncnt++;
            }
            
            cnt = ncnt;
            i = j;
        }
        
        ok &= (cnt <= mid);
        
        if (ok) {
            right = mid;
        } else {
            left = mid;
        }
    }
    
    cout << right << "\n";
}

Compilation message

mousetrap.cpp: In function 'int main()':
mousetrap.cpp:67:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
         freopen(TASK ".in", "r", stdin);
         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
mousetrap.cpp:68:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
         freopen(TASK ".out", "w", stdout);
         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 21 ms 23800 KB Output is correct
2 Correct 20 ms 23912 KB Output is correct
3 Correct 20 ms 23912 KB Output is correct
4 Correct 21 ms 24012 KB Output is correct
5 Correct 21 ms 24012 KB Output is correct
6 Correct 26 ms 24012 KB Output is correct
7 Correct 21 ms 24056 KB Output is correct
8 Correct 21 ms 24056 KB Output is correct
9 Correct 21 ms 24056 KB Output is correct
10 Correct 21 ms 24096 KB Output is correct

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 519 ms 67156 KB Output is correct
2 Correct 548 ms 67156 KB Output is correct
3 Correct 1157 ms 68220 KB Output is correct
4 Correct 529 ms 68220 KB Output is correct
5 Correct 1123 ms 68368 KB Output is correct
6 Correct 1148 ms 68368 KB Output is correct

Subtask #3
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 21 ms 23800 KB Output is correct
2 Correct 20 ms 23912 KB Output is correct
3 Correct 20 ms 23912 KB Output is correct
4 Correct 21 ms 24012 KB Output is correct
5 Correct 21 ms 24012 KB Output is correct
6 Correct 26 ms 24012 KB Output is correct
7 Correct 21 ms 24056 KB Output is correct
8 Correct 21 ms 24056 KB Output is correct
9 Correct 21 ms 24056 KB Output is correct
10 Correct 21 ms 24096 KB Output is correct
11 Correct 20 ms 68368 KB Output is correct
12 Correct 21 ms 68368 KB Output is correct
13 Correct 21 ms 68368 KB Output is correct
14 Correct 21 ms 68368 KB Output is correct
15 Correct 21 ms 68368 KB Output is correct
16 Correct 21 ms 68368 KB Output is correct
17 Correct 21 ms 68368 KB Output is correct
18 Correct 21 ms 68368 KB Output is correct
19 Correct 22 ms 68368 KB Output is correct
20 Correct 21 ms 68368 KB Output is correct
21 Correct 21 ms 68368 KB Output is correct
22 Correct 20 ms 68368 KB Output is correct

Subtask #4
35.0 / 35.0

# Verdict Execution time Memory Grader output
1 Correct 21 ms 23800 KB Output is correct
2 Correct 20 ms 23912 KB Output is correct
3 Correct 20 ms 23912 KB Output is correct
4 Correct 21 ms 24012 KB Output is correct
5 Correct 21 ms 24012 KB Output is correct
6 Correct 26 ms 24012 KB Output is correct
7 Correct 21 ms 24056 KB Output is correct
8 Correct 21 ms 24056 KB Output is correct
9 Correct 21 ms 24056 KB Output is correct
10 Correct 21 ms 24096 KB Output is correct
11 Correct 519 ms 67156 KB Output is correct
12 Correct 548 ms 67156 KB Output is correct
13 Correct 1157 ms 68220 KB Output is correct
14 Correct 529 ms 68220 KB Output is correct
15 Correct 1123 ms 68368 KB Output is correct
16 Correct 1148 ms 68368 KB Output is correct
17 Correct 20 ms 68368 KB Output is correct
18 Correct 21 ms 68368 KB Output is correct
19 Correct 21 ms 68368 KB Output is correct
20 Correct 21 ms 68368 KB Output is correct
21 Correct 21 ms 68368 KB Output is correct
22 Correct 21 ms 68368 KB Output is correct
23 Correct 21 ms 68368 KB Output is correct
24 Correct 21 ms 68368 KB Output is correct
25 Correct 22 ms 68368 KB Output is correct
26 Correct 21 ms 68368 KB Output is correct
27 Correct 21 ms 68368 KB Output is correct
28 Correct 20 ms 68368 KB Output is correct
29 Correct 21 ms 68368 KB Output is correct
30 Correct 515 ms 80880 KB Output is correct
31 Correct 516 ms 94364 KB Output is correct
32 Correct 519 ms 217220 KB Output is correct
33 Correct 507 ms 230704 KB Output is correct
34 Correct 1158 ms 230704 KB Output is correct
35 Correct 1185 ms 230704 KB Output is correct
36 Correct 1190 ms 230704 KB Output is correct
37 Correct 1172 ms 230704 KB Output is correct
38 Correct 1016 ms 230704 KB Output is correct
39 Correct 1006 ms 230704 KB Output is correct
40 Correct 1031 ms 230704 KB Output is correct