Submission #707673

#	Time	Username	Problem	Language	Result	Execution time	Memory
707673		ThMinh_	Bridges (APIO19_bridges)	C++14	100 / 100	2175 ms	10720 KiB

bridges

#include<bits/stdc++.h>
#define forin(i,a,b) for(int i=a;i<=b;++i)
using namespace std;
const int N = 5e4 + 10;
int n, m, p, s = 1e3;
int vis[N << 1], ans[N << 1], par[N];
struct brg {
    int u, v, w;
};
brg e[N << 1];
struct quest {
    int t, b, r, w, s, i;
};
quest q[N << 1];
stack<pair<int, int>> rb;
int root(int x) {
    if(par[x] < 0) return x;
    return root(par[x]);
}
void join(int u, int v, int task) {
    u = root(u);
    v = root(v);
    if(u == v) return;
    if(par[u] > par[v]) swap(u, v);
    if(task) {
        rb.push({u, par[u]});
        rb.push({v, par[v]});
    }
    par[u] += par[v];
    par[v] = u;
}
void relife() {
    while(!rb.empty()) {
        int u, p; tie(u, p) = rb.top(); rb.pop();
        par[u] = p;
    }
}
int main () {
    cin.tie(0)->sync_with_stdio(0);
    if(fopen("Task.inp","r")) {
        freopen("Task.inp","r",stdin);
        freopen("WA.out","w",stdout);
    }
    cin>>n>>m;
    forin(i,1,m) {
        int u, v, w; cin>>u>>v>>w;
        e[i] = {u, v, w};
    }
    cin>>p;
    forin(i,1,p) {
        cin>>q[i].t;
        if(q[i].t == 1) cin>>q[i].b>>q[i].r;
        else cin>>q[i].s>>q[i].w;
    }
    forin(blk,0,s) {
        int f = blk * s + 1;
        int l = min(p, (blk + 1) * s);
        if(f > l) break;
        fill(par + 1, par + n + 1, -1);
        fill(vis + 1, vis + m + 1, 0);
        vector<brg> rem;
        vector<quest> emilia;
        forin(i,f,l) {
            if(q[i].t == 1) vis[q[i].b] = 1;
            else {
                quest aa = q[i]; aa.i = i;
                emilia.push_back(aa);
            }
        }
        forin(i,1,m) if(!vis[i]) rem.push_back(e[i]);
        sort(rem.begin(), rem.end(), [] (brg x, brg y) {
            return x.w < y.w;
        });
        sort(emilia.begin(), emilia.end(), [] (quest x, quest y) {
            return x.w > y.w;
        });
        int j = 0;
        forin(i,f,l) if(q[i].t == 1) vis[q[i].b] = e[q[i].b].w;
        for(auto Q : emilia) {
            int s = Q.s, w = Q.w, i = Q.i;
            while(!rem.empty() && rem.back().w >= w) {
                join(rem.back().u, rem.back().v, 0);
                rem.pop_back();
            }
            forin(o,f,i) if(q[o].t == 1) e[q[o].b].w = q[o].r;
            forin(o,f,l) if(q[o].t == 1 && e[q[o].b].w >= w){
                join(e[q[o].b].u, e[q[o].b].v, 1);
            }
            forin(o,f,l) if(q[o].t == 1) e[q[o].b].w = vis[q[o].b];
            s = root(s);
            ans[i] = abs(par[s]);
            relife();
        }
        forin(i,f,l) if(q[i].t == 1) e[q[i].b].w = q[i].r;
    }
    forin(i,1,p) if(q[i].t == 2) cout<<ans[i]<<"\n";
}

Compilation message (stderr)

bridges.cpp: In function 'int main()':
bridges.cpp:77:13: warning: unused variable 'j' [-Wunused-variable]
   77 |         int j = 0;
      |             ^
bridges.cpp:41:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   41 |         freopen("Task.inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
bridges.cpp:42:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   42 |         freopen("WA.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