Submission #556276

#	Time	Username	Problem	Language	Result	Execution time	Memory
556276		Tien_Noob	Bridges (APIO19_bridges)	C++17	100 / 100	2127 ms	131304 KiB

bridges

//Make CSP great again
//Vengeance
#include <bits/stdc++.h>
#define TASK "TESTCODE"
#define Log2(x) 31 - __builtin_clz(x)
using namespace std;
const int block = 1000, M = 1e5, N = 5e4;
stack<tuple<int, int, int > > st;
int lab[N + 1], n, m, a[M + 1], b[M + 1], w[M + 1], t[M + 1], x[M + 1], y[M + 1], q, res[M + 1];
bitset<M + 1> changed;
vector<int> upt[M + 1];
int FindSet(int u)
{
    return lab[u] < 0 ? u : FindSet(lab[u]);
}
void Unite(int u, int v)
{
    u = FindSet(u);
    v = FindSet(v);
    if (u == v)
    {
        return ;
    }
    if (lab[u] > lab[v])
    {
        swap(u, v);
    }
    lab[u] += lab[v];
    st.push(make_tuple(u, v, lab[v]));
    lab[v] = u;
}
void roll_back(int sz)
{
    while(st.size() > sz)
    {
        int u, v, s;
        tie(u, v, s) = st.top();
        st.pop();
        lab[u] -= s;
        lab[v] = s;
    }
}
void read()
{
    cin >> n >> m;
    for (int i = 1; i <= m; ++ i)
    {
        cin >> a[i] >> b[i] >> w[i];
    }
    cin >> q;
    for (int i = 1; i <= q; ++ i)
    {
        cin >> t[i] >> x[i] >> y[i];
    }
}
void solve()
{
    for (int l = 1; l <= q; l+= block)
    {
        int r = min(q, l + block - 1);
        changed.reset();
        memset(lab, -1, sizeof(lab));
        while(!st.empty())
        {
            st.pop();
        }
        vector<int> tmp, query;
        for (int i = l; i <= r; ++ i)
        {
            if (t[i] == 1)
            {
                changed[x[i]] = true;
                tmp.push_back(x[i]);
            }
        }
        vector<int> unchanged;
        for (int i = 1; i <= m; ++ i)
        {
            if (!changed[i])
            {
                unchanged.push_back(i);
            }
        }
        sort(unchanged.begin(), unchanged.end(), [&](const int &a, const int &b)
             {
                 return w[a] < w[b];
             });
        for (int i = l; i <= r; ++ i)
        {
            if (t[i] == 1)
            {
                w[x[i]] = y[i];
                //tmp.push_back(i);
            }
            else
            {
                for (int j : tmp)
                {
                    if (w[j] >= y[i])
                    {
                        upt[i].push_back(j);
                    }
                }
                query.push_back(i);
            }
        }
        sort(query.begin(), query.end(), [&](const int & a, const int &b)
             {
                 return y[a] > y[b];
             });
        for (int i : query)
        {
            //cerr << i << '\n';
            while(!unchanged.empty() && w[unchanged.back()] >= y[i])
            {
                //cerr << unchanged.back() << ' ';
                Unite(a[unchanged.back()], b[unchanged.back()]);
                unchanged.pop_back();
            }
            //cerr << '\n';
            int sz = st.size();
            for (int j : upt[i])
            {
                Unite(a[j], b[j]);
                //cerr << j << ' ';
            }
            //cerr << '\n';
            res[i] = -lab[FindSet(x[i])];
            roll_back(sz);
            //cerr << '\n';
        }
    }
    for (int i = 1; i <= q; ++ i)
    {
        if (t[i] == 1)
        {
            continue;
        }
        cout << res[i] << '\n';
    }
}
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    if (fopen(TASK".INP", "r"))
    {
        freopen(TASK".INP", "r", stdin);
        //freopen(TASK".OUT", "w", stdout);
    }
    int t = 1;
    bool typetest = false;
    if (typetest)
    {
        cin >> t;
    }
    for (int __ = 1; __ <= t; ++ __)
    {
        //cout << "Case " << __ << ": ";
        read();
        solve();
    }
}

Compilation message (stderr)

bridges.cpp: In function 'void roll_back(int)':
bridges.cpp:34:21: warning: comparison of integer expressions of different signedness: 'std::stack<std::tuple<int, int, int> >::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   34 |     while(st.size() > sz)
      |           ~~~~~~~~~~^~~~
bridges.cpp: In function 'int main()':
bridges.cpp:148:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  148 |         freopen(TASK".INP", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 13 / 13
• Subtask 2: 16 / 16
• Subtask 3: 17 / 17
• Subtask 4: 14 / 14
• Subtask 5: 13 / 13
• Subtask 6: 27 / 27