Submission #938257

#	Time	Username	Problem	Language	Result	Execution time	Memory
938257		Zero_OP	Bridges (APIO19_bridges)	C++14	100 / 100	2965 ms	58208 KiB

bridges

#include<bits/stdc++.h>

using namespace std;
using int64 = int64_t;

#define     REP(i, n) for(int i = 0, _n = n; i < _n; ++i)
#define    REPD(i, n) for(int i = n - 1; i >= 0; --i)
#define  FOR(i, l, r) for(int i = l, _r = r; i <= _r; ++i)
#define FORD(i, r, l) for(int i = r, _l = l; i >= _l; --i)
#define          left __left
#define         right __right
#define          prev __prev
#define          next __next
#define           div __div
#define            pb push_back
#define            pf push_front
#define         sz(v) (int)v.size()
#define      range(v) begin(v), end(v)
#define    compact(v) v.erase(unique(range(v)), end(v))
#define      debug(v) "[" #v " = " << (v) << "]"

template<typename T>
    bool minimize(T& a, const T& b){
        if(a > b){
            a = b;
            return true;
        }
        return false;
    }

template<typename T>
    bool maximize(T& a, const T& b){
        if(a < b){
            a = b;
            return true;
        }
        return false;
    }

template<int dimension, class T>
struct vec : public vector<vec<dimension - 1, T>> {
    static_assert(dimension > 0, "Dimension must be positive !\n");
    template<typename... Args>
    vec(int n = 0, Args... args) : vector<vec<dimension - 1, T>>(n, vec<dimension - 1, T>(args...)) {}
};

template<class T>
struct vec<1, T> : public vector<T> {
    vec(int n = 0, T val = T()) : vector<T>(n, val) {}
};

void init(void);
void process(void);

int main(){
    ios_base::sync_with_stdio(0); cin.tie(0);

    #define task "antuvu"
    if(fopen(task".inp", "r")){
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    }

    int T = 1; //cin >> T;
    while(T--) {
        init();
        process();
    }

    return 0;
}

const int N = 1e5 + 5;
const int B = 400;

int n, m, q, u[N], v[N], d[N], t[N], a[N], b[N], ans[N];
bool modified[N];
vector<int> edges[N];

struct DisjointSet{
    stack<tuple<int, int, int, int>> operations;
    vector<int> lab;
    DisjointSet(int n) : lab(n, -1), operations() {}

    int root(int u){
        return lab[u] < 0 ? u : root(lab[u]);
    }

    bool unite(int u, int v){
        u = root(u), v = root(v);
        if(u == v) return false;
        if(lab[u] > lab[v]) swap(u, v);
        operations.push({u, lab[u], v, lab[v]});
        lab[u] += lab[v]; lab[v] = u;
        return true;
    }

    bool same_set(int u, int v){
        return root(u) == root(v);
    }

    int get_size(int u){
        return -lab[root(u)];
    }

    void rollback(){
        int u, pu, v, pv;
        tie(u, pu, v, pv) = operations.top(); operations.pop();
        lab[u] = pu;
        lab[v] = pv;
    }

    void roll(int cnt){
        while(cnt--) rollback();
    }

    void reset(){
        while(!operations.empty()) operations.pop();
        fill(range(lab), -1);
    }
};

void init(){
    cin >> n >> m;
    REP(i, m){
        cin >> u[i] >> v[i] >> d[i];
        --u[i], --v[i];
    }

    cin >> q;
    REP(i, q){
        cin >> t[i] >> a[i] >> b[i]; --a[i];
    }
}

void process(){
    DisjointSet dsu(n);
    for(int l = 0; l < q; l += B){
        int r = min(l + B - 1, q - 1);
        dsu.reset(); memset(modified, false, sizeof(modified));

        vector<int> updates, queries;
        FOR(i, l, r){
            if(t[i] == 1){
                modified[a[i]] = true;
                updates.pb(i);
            }
            else queries.push_back(i);
        }

        vector<int> unchanged_edges;
        REP(i, m) if(!modified[i]) unchanged_edges.pb(i);
        sort(range(unchanged_edges), [&](int i, int j){ return d[i] > d[j]; });
        sort(range(queries), [&](int i, int j){ return b[i] > b[j]; });

        FOR(i, l, r){
            if(t[i] == 1){
                d[a[i]] = b[i];
            }
            else{
                for(int x : updates){
                    if(d[a[x]] >= b[i]){
                        edges[i].pb(a[x]);
                    }
                }
            }
        }


        int j = 0;
        REP(i, sz(queries)){
            int id = queries[i];
            while(j < sz(unchanged_edges) && d[unchanged_edges[j]] >= b[id]){
                dsu.unite(u[unchanged_edges[j]], v[unchanged_edges[j]]);
                ++j;
            }

            int cnt = 0;
            for(int k : edges[id]) {
                cnt += dsu.unite(u[k], v[k]);
            }
            ans[id] = dsu.get_size(a[id]);
            dsu.roll(cnt);
        }
    }

    REP(i, q){
        if(t[i] == 2) cout << ans[i] << '\n';
    }
}

Compilation message (stderr)

bridges.cpp: In constructor 'DisjointSet::DisjointSet(int)':
bridges.cpp:82:17: warning: 'DisjointSet::lab' will be initialized after [-Wreorder]
   82 |     vector<int> lab;
      |                 ^~~
bridges.cpp:81:38: warning:   'std::stack<std::tuple<int, int, int, int> > DisjointSet::operations' [-Wreorder]
   81 |     stack<tuple<int, int, int, int>> operations;
      |                                      ^~~~~~~~~~
bridges.cpp:83:5: warning:   when initialized here [-Wreorder]
   83 |     DisjointSet(int n) : lab(n, -1), operations() {}
      |     ^~~~~~~~~~~
bridges.cpp: In function 'int main()':
bridges.cpp:60:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   60 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
bridges.cpp:61:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   61 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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