Submission #310488

#	Time	Username	Problem	Language	Result	Execution time	Memory
310488		wiwiho	Swapping Cities (APIO20_swap)	C++14	100 / 100	681 ms	75928 KiB

swap

//#define NDEBUG

#include "swap.h"

#include <bits/stdc++.h>
#include <bits/extc++.h>

#define StarBurstStream ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define iter(a) a.begin(), a.end()
#define riter(a) a.rbegin(), a.rend()
#define lsort(a) sort(iter(a))
#define gsort(a) sort(riter(a))
#define pb(a) push_back(a)
#define eb(a) emplace_back(a)
#define pf(a) push_front(a)
#define pob pop_back()
#define pof pop_front()
#define mp(a, b) make_pair(a, b)
#define F first
#define S second
#define mt make_tuple
#define gt(t, i) get<i>(t)
#define iceil(a, b) ((a + b - 1) / b)
#define tomax(a, b) (a = max(a, b))
#define printv(a, b) {bool pvaspace=false; \
for(auto pva : a){ \
    if(pvaspace) b << " "; pvaspace=true;\
    b << pva;\
}\
b << "\n";}

//#define TEST

using namespace std;
using namespace __gnu_pbds;

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;

using pii = pair<int, int>;
using pll = pair<ll, ll>;
using pdd = pair<ld, ld>;
using tiii = tuple<int, int, int>;

const ll MOD = 1000000007;
const ll MAX = 2147483647;

template<typename A, typename B>
ostream& operator<<(ostream& o, pair<A, B> p){
    return o << '(' << p.F << ',' << p.S << ')';
}

vector<int> dsu, one, three;
vector<vector<int>> anc, g;
vector<int> ans, in, out;

int findDSU(int a){
    if(dsu[a] != a) dsu[a] = findDSU(dsu[a]);
    return dsu[a];
}

void unionDSU(int a, int b){
    a = findDSU(a); b = findDSU(b);
    if(a == b) return;
    dsu[b] = a;
    one[a] += one[b];
    three[a] += three[b];
}

int dfsts = 0;
void dfs(int now, int p){
    in[now] = dfsts++;
    if(ans[now] == -1) ans[now] = ans[p];
    for(int i : g[now]) dfs(i, now);
    out[now] = dfsts++;
}

bool isAnc(int a, int b){
    return in[a] <= in[b] && out[a] >= out[b];
}

int lca(int a, int b){
    if(isAnc(a, b)) return a;
    for(int i = 19; i >= 0; i--){
        if(!isAnc(anc[a][i], b)) a = anc[a][i];
    }
    return anc[a][0];
}


void init(int N, int M,
          std::vector<int> U, std::vector<int> V, std::vector<int> W) {

    vector<pair<int, pii>> e(M);
    for(int i = 0; i < M; i++){
        e[i] = mp(W[i], mp(U[i], V[i]));
    }
    lsort(e);

    dsu.resize(N + M);
    for(int i = 0; i < N + M; i++) dsu[i] = i;
    one.resize(N + M); three.resize(N + M);

    int ts = N;

    anc.resize(N + M, vector<int>(20));
    for(int i = 0; i < N + M; i++) anc[i][0] = i;
    ans.resize(N + M, -1);
    g.resize(N + M);
    in.resize(N + M);
    out.resize(N + M);

    vector<int> deg(N);

    for(auto i : e){
        int w = i.F, u = i.S.F, v = i.S.S;
        if(deg[u] == 1) one[findDSU(u)]--;
        if(deg[v] == 1) one[findDSU(v)]--;
        deg[u]++; deg[v]++;
        if(deg[u] == 1) one[findDSU(u)]++;
        else if(deg[u] == 3) three[findDSU(u)]++;
        if(deg[v] == 1) one[findDSU(v)]++;
        else if(deg[v] == 3) three[findDSU(v)]++;

        u = findDSU(u);
        v = findDSU(v);
        int dv = ts++;
        if(u == v){
            unionDSU(dv, u);
            anc[u][0] = dv;
            g[dv].eb(u);
        }
        else{
            unionDSU(dv, u);
            unionDSU(dv, v);
            anc[u][0] = anc[v][0] = dv;
            g[dv].eb(u); g[dv].eb(v);
        }

        if(!one[dv] || three[dv]) ans[dv] = w;
    }

//    for(int i = 0; i < N + M; i++) cerr << anc[i][0] << " ";
//    cerr << "\n";

    for(int i = 0; i < N + M; i++){
        if(anc[i][0] == i) dfs(i, i);
    }

    for(int i = 1; i < 20; i++){
        for(int j = 0; j < N + M; j++){
            anc[j][i] = anc[anc[j][i - 1]][i - 1];
        }
    }

}

int getMinimumFuelCapacity(int X, int Y) {
    if(findDSU(X) != findDSU(Y)) return -1;
    return ans[lca(X, Y)];
}

• Subtask 1: 6 / 6
• Subtask 2: 7 / 7
• Subtask 3: 17 / 17
• Subtask 4: 20 / 20
• Subtask 5: 23 / 23
• Subtask 6: 27 / 27