Submission #523196

#	Time	Username	Problem	Language	Result	Execution time	Memory
523196		LptN21	Bridges (APIO19_bridges)	C++14	100 / 100	2687 ms	43544 KiB

bridges

#include <bits/stdc++.h>
using namespace std;
#define fastIO ios_base::sync_with_stdio(false), cin.tie(NULL);
#define PI acos(-1.0)
#define eps 1e-9
#define FF first
#define SS second
// VECTOR (6)
#define pb push_back
#define lb lower_bound
#define ub upper_bound
#define sz(v) int((v).size())
#define all(v) (v).begin(), (v).end()
#define uniq(v) sort(all( (v) )), (v).resize( unique(all( (v) )) - (v).begin() );
// BIT (6)
#define CNTBIT(x) __builtin_popcountll(x)
#define ODDBIT(x) __builtin_parityll(x)
#define MASK(i) (1LL<<(i))
#define BIT(x, i) (((x)>>(i))&1)
#define SUBSET(big, small) (((big)&(small))==(small))
#define MINBIT(x) (x)&(-x)
#define FIRSTBIT(x) __builtin_ctzll(x)
//typedef
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<ll, int> ii;

/* */
template<class T>
bool minimize(T &a, const T &b) {
    if(a > b) {a = b; return 1;}
    return 0;
}
template<class T>
bool maximize(T &a, const T &b) {
    if(a < b) {a = b; return 1;}
    return 0;
}
/* */

/* CODE BELOW */
const int N = 5e4 + 7, M = 1e5 + 7;
const int oo = 1e9 + 7;
const int MOD = 1e9 + 7;

int n, m, q, t;

const int B = 825; // size block

struct Edge{
    int u, v, w;
    bool operator<(const Edge &e) const {
        if(w != e.w) return w < e.w;
        if(u != e.u) return u < e.u;
        return v < e.v;
    }
} e[M];

struct Query{int t, u, w;} qry[M];
bool changedEdge[M];
vector<int> careEdge[B + 7];
int ans[M];

//
int dsu[N], vsz[N];
vector<int> rollback;
int root(int u) {
    while(dsu[u] != u) u = dsu[u];
    return u;
}
bool join(int u, int v) {
    if((u=root(u)) == (v=root(v))) return 0;
    if(dsu[u] < dsu[v]) swap(u, v);
    rollback.pb(v);
    vsz[u]+= vsz[v], dsu[v] = u;
    return 1;
}
void goback(int time) {
    while(sz(rollback)>time) {
        int v = rollback.back();
        vsz[dsu[v]]-=vsz[v];
        dsu[v] = v;
        rollback.pop_back();
    }
}
//

void init() {
    iota(dsu+1, dsu+n+1, 1);
    fill(vsz+1, vsz+n+1, 1);
    //rollback.clear();
}

signed main() {
    //freopen("test.inp", "r", stdin);
    //freopen("test.out", "w", stdout);
    //fastIO;
    scanf("%d%d", &n, &m);
    int u, v, w;
    for(int i=1;i<=m;i++) {
        scanf("%d%d%d", &u, &v, &w);
        e[i] = {u, v, w};
    }
    scanf("%d", &q);
    for(int i=1;i<=q;i++) {
        scanf("%d%d%d", &t, &u, &w);
        qry[i] = {t, u, w};
    }

    for(int r, l=1;l<=q;l = r+1) {
        r = min(q, l+B-1); init();
        vector<int> ask, update, unchanged;
        for(int i=l;i<=r;i++) {
            if(qry[i].t == 1) {
                update.pb(i);
                changedEdge[qry[i].u] = 1;
            } else ask.pb(i);
        }

        for(int i=l;i<=r;i++) {
            if(qry[i].t == 1) {
                e[qry[i].u].w = qry[i].w;
            } else {
                careEdge[i-l+1].clear();
                for(int j:update) {
                    if(e[qry[j].u].w>=qry[i].w) {
                        careEdge[i-l+1].pb(qry[j].u);
                    }
                }
            }
        }
        for(int i=1;i<=m;i++) if(!changedEdge[i]) unchanged.pb(i);

        sort(all(ask), [&] (int x, int y) {return qry[x].w > qry[y].w;});
        sort(all(unchanged), [&] (int x, int y) {return e[x].w > e[y].w;});

        int j = 0;
        for(int i:ask) {
            for(;j<sz(unchanged);j++) {
                int k = unchanged[j];
                if(e[k].w>=qry[i].w) join(e[k].u, e[k].v);
                else break;
            }
            int prvSize = sz(rollback);

            for(int k:careEdge[i-l+1]) {
                //printf("%d | %d %d\n", k, e[k].u, e[k].v);
                join(e[k].u, e[k].v);
            }
            ans[i] = vsz[root(qry[i].u)];
            goback(prvSize);
        }

        for(int i:update) changedEdge[qry[i].u] = 0;
    }

    for(int i=1;i<=q;i++) {
        if(qry[i].t == 2) printf("%d\n", ans[i]);
    }

    return 0;
}

Compilation message (stderr)

bridges.cpp: In function 'int main()':
bridges.cpp:99:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   99 |     scanf("%d%d", &n, &m);
      |     ~~~~~^~~~~~~~~~~~~~~~
bridges.cpp:102:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  102 |         scanf("%d%d%d", &u, &v, &w);
      |         ~~~~~^~~~~~~~~~~~~~~~~~~~~~
bridges.cpp:105:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  105 |     scanf("%d", &q);
      |     ~~~~~^~~~~~~~~~
bridges.cpp:107:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  107 |         scanf("%d%d%d", &t, &u, &w);
      |         ~~~~~^~~~~~~~~~~~~~~~~~~~~~

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