Submission #131181

#	Time	Username	Problem	Language	Result	Execution time	Memory
131181		osaaateiasavtnl	Bridges (APIO19_bridges)	C++14	100 / 100	2405 ms	11620 KiB

bridges

#include<bits/stdc++.h>
using namespace std;
#define app push_back
const int N = 1e5 + 7, K = 600;
struct Edge {
    int u, v, c;
};  
struct Quer {
    int t, i, c;
    bool operator < (Quer p) {
        return c > p.c;
    }   
};  
struct Seg {
    int l, r, i, c;
    bool operator < (Seg p) {
        return c > p.c;
    }   
};
int n, m, q;
int par[N], cnt[N];
void init() {
    for (int i = 1; i <= n; ++i) {
        par[i] = i; cnt[i] = 1;
    }
}   
int root(int u) {
    if (u == par[u]) return u;
    else return par[u] = root(par[u]);
}   
void merge(int u, int v) {
    u = root(u); v = root(v);
    if (u == v) return;
    if (cnt[v] < cnt[u]) swap(u, v);
    par[u] = v; cnt[v] += cnt[u];
}   
Edge ed[N];
Quer d[N];
int lf[N], w[N];
vector <Seg> v;
int ans[N];
bool upd[N];
vector <int> g[N];
bool comp(int i, int j) {
    return d[i].c > d[j].c;
}
bool used[N];
vector <int> vis;
int dfs(int u) {
    int ans = cnt[u];
    used[u] = 1;
    vis.app(u);
    for (int v : g[u]) {
        if (!used[v]) {
            ans += dfs(v);
        }   
    }   
    return ans;
}     
void solve(int L, int R) {
    memset(upd, 0, sizeof upd);
    vector <int> q;
    for (int i = L; i <= R; ++i) {
        if (d[i].t == 1) {
            upd[d[i].i] = 1;
        }
        else {
            q.app(i);
        }   
    }   
    sort(q.begin(), q.end(), comp);
    int ptr = 0;
    vector <Seg> t;
    init();
    for (int i : q) {
        while (ptr < v.size() && v[ptr].c >= d[i].c) {
            if (R < v[ptr].l || v[ptr].r < L) {
                   
            }
            else if (v[ptr].l <= L && R <= v[ptr].r) {
                int e = v[ptr].i;
                merge(ed[e].u, ed[e].v);
            }
            else {
                t.app(v[ptr]);
            }   
            ++ptr;
        }   
        for (auto s : t) {
            if (s.l <= i && i <= s.r) {
                int u = root(ed[s.i].u), v = root(ed[s.i].v);
                g[u].app(v); g[v].app(u);
            }   
        }   
        ans[i] = dfs(root(d[i].i));
        for (int e : vis) used[e] = 0;
        vis.clear();
        for (auto s : t) {
            if (s.l <= i && i <= s.r) {
                int u = root(ed[s.i].u), v = root(ed[s.i].v);
                g[u].clear(); g[v].clear();
            }   
        }   
    }   
}   
signed main() {
    #ifdef HOME
    freopen("input.txt", "r", stdin);
    #else
    ios_base::sync_with_stdio(0); cin.tie(0);
    #endif
    cin >> n >> m;
    for (int i = 0; i < m; ++i) {
        cin >> ed[i].u >> ed[i].v >> ed[i].c;
        w[i] = ed[i].c;
    }   
    cin >> q;
    for (int i = 0; i < q; ++i) {
        cin >> d[i].t >> d[i].i >> d[i].c;
        if (d[i].t == 1) {
            --d[i].i;
            v.app({lf[d[i].i], i - 1, d[i].i, w[d[i].i]});
            lf[d[i].i] = i;
            w[d[i].i] = d[i].c;
        }   
    }   
    for (int i = 0; i < m; ++i) {
        v.app({lf[i], q - 1, i, w[i]});
    }   
    sort(v.begin(), v.end());
    for (int a = 0; ; ++a) {
        int L = a * K;
        int R = min(L + K - 1, q - 1);
        if (R < L) break;
        solve(L, R);
    }   
    for (int i = 0; i < q; ++i) {
        if (d[i].t == 2) cout << ans[i] << '\n';
    }   
}   

Compilation message (stderr)

bridges.cpp: In function 'void solve(int, int)':
bridges.cpp:76:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         while (ptr < v.size() && v[ptr].c >= d[i].c) {
                ~~~~^~~~~~~~~~

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