oj.uz

Submission #162285

# Submission time Handle Problem Language Result Execution time Memory
162285 2019-11-07T12:53:40 Z HellAngel Mousetrap (CEOI17_mousetrap) C++14
45 / 100
 1392 ms 99092 KB 
#include <bits/stdc++.h>
#define int long long

using namespace std;
const int maxn = 1e6 + 7;
int FastIn()
{
    char c;
    while(true)
    {
        c = getchar();
        if(c >= '0' && c <= '9') break;
    }
    int ans = c- '0';
    while(true)
    {
        c = getchar();
        if(c > '9' || c < '0') return ans;
        ans = ans * 10 + c - '0';
    }
}
int n, m, t, cnt, sum, dp[maxn], cur[maxn];

vector<int> st;

bool found;
vector<int> vt[maxn], path, gau[maxn];

void DFS(int u, int p)
{
    if(u == t)
    {
        path.push_back(u);
        found = true;
        return;
    }
    for(auto v: vt[u])
    {
        if(v == p) continue;
        DFS(v, u);
        if(found)
        {
            path.push_back(u);
            break;
        }
    }
}

void Solve(int u, int p)
{
    vector<int> cac = {};
    int sum = -1;
    for(auto v: vt[u])
    {
        if(v == p) continue;
        Solve(v, u);
        sum++;
        cac.push_back(dp[v]);
    }
    sort(cac.begin(), cac.end());
    if(cac.size())
    {
        cac.pop_back();
        if(cac.size() == 0) dp[u] = 1;
        else dp[u] = sum + cac.back() + 1;
    }
    else dp[u] = 0;
}

bool Check(int x)
{
    st = {};
    for(int i = 0; i + 1 < path.size(); i++)
    {
        cur[i + 1] = (int)gau[i + 1].size() - 1;
        int u = path[i];
        for(auto v: vt[u])
        {
            if(v == path[i + 1]) continue;
            if(i > 0 && v == path[i - 1]) continue;
            if(dp[v] > x) st.push_back(i + 1);
        }
    }
    int cnt = path.size() - 1;
    sort(st.begin(), st.end(), greater<int>());
    for(int i = 1; i <= cnt; i++)
    {
        if(st.empty()) return true;
        cur[st.back()]--;
        st.pop_back();
        if(cur[i] >= 0 && gau[i][cur[i]] > x) return false;

    }
    return true;
}

int32_t main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    if(fopen("test.inp", "r")) freopen("test.inp", "r", stdin), freopen("test.out", "w", stdout);
    n = FastIn();
    t = FastIn();
    m = FastIn();
    for(int i = 1; i < n; i++)
    {
        int u, v;
        u = FastIn();
        v = FastIn();
        vt[u].push_back(v);
        vt[v].push_back(u);
    }
    DFS(m, m);
    reverse(path.begin(), path.end());
    for(int i = 0; i + 1 < path.size(); i++)
    {
        gau[i + 1] = {};
        int u = path[i];
        for(auto v: vt[u])
        {
            if(v == path[i + 1]) continue;
            if(i > 0 && v == path[i - 1]) continue;
            Solve(v, u);
            sum++;
            gau[i + 1].push_back(dp[v]);
        }
        sort(gau[i + 1].begin(), gau[i + 1].end());
    }
    int l = 0;
    int r = 1e9;
    while(l <= r)
    {
        int mid = l + r >> 1;
        if(Check(mid)) r = mid - 1;
        else l = mid + 1;
    }
    cout << sum + l;
}

Compilation message

mousetrap.cpp: In function 'bool Check(long long int)':
mousetrap.cpp:73:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0; i + 1 < path.size(); i++)
                    ~~~~~~^~~~~~~~~~~~~
mousetrap.cpp: In function 'int32_t main()':
mousetrap.cpp:115:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0; i + 1 < path.size(); i++)
                    ~~~~~~^~~~~~~~~~~~~
mousetrap.cpp:133:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
         int mid = l + r >> 1;
                   ~~^~~
mousetrap.cpp:101:63: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
     if(fopen("test.inp", "r")) freopen("test.inp", "r", stdin), freopen("test.out", "w", stdout);
                                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
mousetrap.cpp:101:63: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]

Subtask #1
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 51 ms 47352 KB Output is correct
2 Correct 51 ms 47352 KB Output is correct
3 Correct 49 ms 47480 KB Output is correct
4 Correct 51 ms 47284 KB Output is correct
5 Correct 50 ms 47352 KB Output is correct
6 Correct 51 ms 47352 KB Output is correct
7 Correct 50 ms 47364 KB Output is correct
8 Correct 49 ms 47352 KB Output is correct
9 Correct 49 ms 47352 KB Output is correct
10 Correct 51 ms 47272 KB Output is correct

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 475 ms 99092 KB Output is correct
2 Correct 434 ms 94456 KB Output is correct
3 Correct 1170 ms 97428 KB Output is correct
4 Correct 601 ms 76408 KB Output is correct
5 Correct 1392 ms 97528 KB Output is correct
6 Correct 1373 ms 97480 KB Output is correct

Subtask #3
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 51 ms 47352 KB Output is correct
2 Correct 51 ms 47352 KB Output is correct
3 Correct 49 ms 47480 KB Output is correct
4 Correct 51 ms 47284 KB Output is correct
5 Correct 50 ms 47352 KB Output is correct
6 Correct 51 ms 47352 KB Output is correct
7 Correct 50 ms 47364 KB Output is correct
8 Correct 49 ms 47352 KB Output is correct
9 Correct 49 ms 47352 KB Output is correct
10 Correct 51 ms 47272 KB Output is correct
11 Correct 48 ms 47352 KB Output is correct
12 Correct 48 ms 47352 KB Output is correct
13 Correct 51 ms 47312 KB Output is correct
14 Correct 50 ms 47480 KB Output is correct
15 Correct 49 ms 47352 KB Output is correct
16 Incorrect 51 ms 47352 KB Output isn't correct
17 Halted 0 ms 0 KB -

Subtask #4
0 / 35.0

# Verdict Execution time Memory Grader output
1 Correct 51 ms 47352 KB Output is correct
2 Correct 51 ms 47352 KB Output is correct
3 Correct 49 ms 47480 KB Output is correct
4 Correct 51 ms 47284 KB Output is correct
5 Correct 50 ms 47352 KB Output is correct
6 Correct 51 ms 47352 KB Output is correct
7 Correct 50 ms 47364 KB Output is correct
8 Correct 49 ms 47352 KB Output is correct
9 Correct 49 ms 47352 KB Output is correct
10 Correct 51 ms 47272 KB Output is correct
11 Correct 475 ms 99092 KB Output is correct
12 Correct 434 ms 94456 KB Output is correct
13 Correct 1170 ms 97428 KB Output is correct
14 Correct 601 ms 76408 KB Output is correct
15 Correct 1392 ms 97528 KB Output is correct
16 Correct 1373 ms 97480 KB Output is correct
17 Correct 48 ms 47352 KB Output is correct
18 Correct 48 ms 47352 KB Output is correct
19 Correct 51 ms 47312 KB Output is correct
20 Correct 50 ms 47480 KB Output is correct
21 Correct 49 ms 47352 KB Output is correct
22 Incorrect 51 ms 47352 KB Output isn't correct
23 Halted 0 ms 0 KB -