Submission #130574

#	Time	Username	Problem	Language	Result	Execution time	Memory
130574		osaaateiasavtnl	Bridges (APIO19_bridges)	C++14	30 / 100	3041 ms	8980 KiB

bridges

#include<bits/stdc++.h>
using namespace std;
#define app push_back
struct Edge {
    int u, v, c;
};  
const int K = 600;
const int N = 1e5 + 7;
int ans[N];
Edge ed[N];
int par[N], cnt[N];
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];
}   
struct Quer {
    int t, i, c;
};
Quer d[N];
bool comp(int i, int j) {
    return ed[i].c > ed[j].c;
}   
bool comp_quer(int i, int j) {
    return d[i].c > d[j].c;
}   
vector <int> g[N];
bool used[N];

bool dfs_used[N];
vector <int> vis;
int dfs(int u) {
    dfs_used[u] = 1;
    vis.app(u);
    int ans = cnt[u];
    for (int v : g[u]) {
        if (!dfs_used[v]) {
            ans += dfs(v);
        }   
    }   
    return ans;
}   
int mem[N];
signed main() {
    #ifdef HOME
    freopen("input.txt", "r", stdin);
    #else
    ios_base::sync_with_stdio(0); cin.tie(0);
    #endif                             
    int n, m;
    cin >> n >> m;
    for (int i = 0; i < m; ++i) {
        cin >> ed[i].u >> ed[i].v >> ed[i].c;
    }   
    int q;
    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;
    }   
    for (int a = 0; ; ++a) {
        if (a * K >= q) break;
        memset(used, 0, sizeof used);
        vector <int> quer;
        for (int b = 0; b < K; ++b) {
            int i = a * K + b;
            if (i >= q) break;
            if (d[i].t == 1) {
                used[d[i].i] = 1;
            }
            else {
                quer.app(i);
            }   
        }   
        vector <int> us, nus;
        for (int i = 0; i < m; ++i) {
            if (used[i]) {
                us.app(i);
            }   
            else {
                nus.app(i);
            }   
        }   
        sort(nus.begin(), nus.end(), comp);
        sort(quer.begin(), quer.end(), comp_quer);
        for (int i = 1; i <= n; ++i) {
            par[i] = i; cnt[i] = 1;
        }
        for (int i = 0; i < m; ++i) {
            mem[i] = ed[i].c;
        }   
        int ptr = 0;
        for (int i : quer) {
            while (ptr < nus.size() && ed[nus[ptr]].c >= d[i].c) {
                merge(ed[nus[ptr]].u, ed[nus[ptr]].v);
                ++ptr;
            }   
            for (int b = 0; b < K; ++b) {
                int j = a * K + b;
                if (j >= q) break;
                int e = d[j].i;
                if (d[j].t == 1) ed[e].c = mem[e];
            }   
            for (int b = 0; b < K; ++b) {
                int j = a * K + b;
                if (j >= i) break;
                int e = d[j].i;
                if (d[j].t == 1) ed[e].c = d[j].c;
            }               
            for (int e : us) {
                if (ed[e].c >= d[i].c) {
                    int u = root(ed[e].u), v = root(ed[e].v);
                    g[u].app(v); g[v].app(u);
                }
            }
            ans[i] = dfs(root(d[i].i));
            for (int e : vis) {
                dfs_used[e] = 0;
            }   
            vis.clear();
            for (int e : us) {
                int u = root(ed[e].u), v = root(ed[e].v);
                g[u].clear(); g[v].clear();
            }              
        }   
        for (int b = 0; b < K; ++b) {
            int i = a * K + b;
            if (i >= q) break;
            if (d[i].t == 1) {
                ed[d[i].i].c = d[i].c;
            }   
        }               
    }   
    for (int i = 0; i < q; ++i) {
        if (d[i].t == 2) {
            cout << ans[i] << '\n';
        }
    }   
}   

Compilation message (stderr)

bridges.cpp: In function 'int main()':
bridges.cpp:99:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             while (ptr < nus.size() && ed[nus[ptr]].c >= d[i].c) {
                    ~~~~^~~~~~~~~~~~

• Subtask 1: 13 / 13
• Subtask 2: 0 / 16
• Subtask 3: 17 / 17
• Subtask 4: 0 / 14
• Subtask 5: 0 / 13
• Subtask 6: 0 / 27