Submission #820171

#	Time	Username	Problem	Language	Result	Execution time	Memory
820171		PenguinsAreCute	Bridges (APIO19_bridges)	C++17	100 / 100	1621 ms	98004 KiB

bridges

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define fi first
#define se second
#define mp make_pair
#define pb push_back
#define LL_MAX LONG_LONG_MAX
#define LL_MIN LONG_LONG_MIN
#define speed ios_base::sync_with_stdio(false); cin.tie(0)
#define stMx(a,b) a = max(a,b)
#define stMn(a,b) a = min(a,b)
typedef pair<int,int> ii;
typedef vector<int> vi;
typedef set<int> si;
typedef vector<ii> vii;
typedef set<ii> sii;
#define REP(i, a, b) for(int i = a; i < b; i++)
#define HASTC 0
#define B 1000
int par[121010], sz[121010];
int u[121010], v[121010], w[121010];
int t[B+5], f[B+5], s[B+5], ans[B+5];
vi join_edge[B+5];
bool changed[121010];
stack<int> onions;
// onion find disjoint sets (with rollbacks)
int find_set(int x) {
    while(x!=par[x]) x=par[x];
    return x;
}
void onion(int x, int y) {
    x=find_set(x),y=find_set(y);
    if(x==y) {onions.push(-1); return;}
    if(sz[x]<sz[y]) swap(x,y);
    onions.push(y);
    par[y]=x; sz[x]+=sz[y];
}
void rollback() {
    assert(!onions.empty());
    if(onions.top()!=-1) {
        sz[par[onions.top()]]-=sz[onions.top()];
        par[onions.top()]=onions.top();
    }
    onions.pop();
}
void init_bucket() {
    iota(par,par+121010,0);
    fill(sz,sz+121010, 1);
    fill(changed,changed+121010,false);
}
void solvetc(int idx) {
    int n, m, q; cin >> n >> m;
    REP(i,0,m) {cin>>u[i]>>v[i]>>w[i]; u[i]--,v[i]--;}
    cin>>q;
    for(int i=0; i<q; i+=B) {
        init_bucket();
        vi qry, upd, nUpd;
        int j=min(q,i+B);
        REP(k,i,j) {
            cin>>t[k-i]>>f[k-i]>>s[k-i];
            if(t[k-i]==1) {upd.pb(k-i); changed[--f[k-i]]=1;}
            else qry.pb(k-i), f[k-i]--;
        }
        REP(k,0,m) if(!changed[k]) nUpd.pb(k);
        REP(k,i,j) {
            if(t[k-i]==1) w[f[k-i]]=s[k-i];
            else {
                join_edge[k-i].clear();
                for(auto l: upd) if(w[f[l]]>=s[k-i]) join_edge[k-i].pb(f[l]);
            }
        }
        sort(qry.begin(),qry.end(),[](int a, int b){return s[a]>s[b];});
        sort(nUpd.begin(),nUpd.end(),[](int a, int b){return w[a]>w[b];});
        int ptr=0;
        for(auto k: qry) {
            while(ptr<nUpd.size()&&w[nUpd[ptr]]>=s[k]) {
                onion(u[nUpd[ptr]],v[nUpd[ptr]]);
                ptr++;
            }
            for(auto l: join_edge[k]) onion(u[l],v[l]);
            ans[k]=sz[find_set(f[k])];
            for(auto l: join_edge[k]) rollback();
        }
        REP(k,i,j) if(t[k-i]==2) cout<<ans[k-i]<<"\n";
    }
}
int32_t main() {
	ios_base::sync_with_stdio(false); cin.tie(0);
    int tc;
    if(HASTC) cin>>tc;
    else tc=1;
    for(int i=0;i<tc;i++) solvetc(i);    
}

Compilation message (stderr)

bridges.cpp: In function 'void solvetc(long long int)':
bridges.cpp:77:22: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   77 |             while(ptr<nUpd.size()&&w[nUpd[ptr]]>=s[k]) {
      |                   ~~~^~~~~~~~~~~~
bridges.cpp:83:22: warning: unused variable 'l' [-Wunused-variable]
   83 |             for(auto l: join_edge[k]) rollback();
      |                      ^

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