제출 #491350

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
491350		qwerasdfzxcl	Simurgh (IOI17_simurgh)	C++14	51 / 100	255 ms	5108 KiB

simurgh

#include "simurgh.h"
#include <bits/stdc++.h>

using namespace std;
typedef long long ll;
const int INF = 1e9;
struct DSU{
    int path[505];
    void init(int n){for (int i=0;i<=n;i++) path[i] = i;}
    int find(int s){
        if (path[s]==s) return s;
        return path[s] = find(path[s]);
    }
    bool merge(int s, int v){
        int x = find(s), y = find(v);
        if (x==y) return 0;
        path[x] = y;
        return 1;
    }
}dsu;
int adj[505][505], n, val[100100], dfs_chk[100100];
bool visited[505];
vector<int> U, V, DV, E, F, adj2[505];

void dfs(int s){
    visited[s] = 1;
    for (int i=0;i<n;i++) if (!visited[i] && adj[s][i]!=-1){
        DV.push_back(adj[s][i]);
        dfs_chk[adj[s][i]] = 1;
        adj2[s].push_back(i);
        adj2[i].push_back(s);
        dfs(i);
    }
}

bool find_path(int s, int e){
    if (s==e) return 1;
    visited[s] = 1;
    for (auto &v:adj2[s]) if (!visited[v]){
        E.push_back(adj[s][v]);
        if (find_path(v, e)) return 1;
        E.pop_back();
    }
    return 0;
}

int calc(int p, int l, int r){
    if (l>r) return 0;
    //printf("calc: %d %d %d\n", p, l, r);
    dsu.init(n);
    vector<int> Q;
    for (int i=l;i<=r;i++) if (adj[p][i]!=-1){
        Q.push_back(adj[p][i]);
        dsu.merge(p, i);
    }

    int cnt = 0;
    for (auto &t:DV) if (dsu.merge(U[t], V[t])){
        Q.push_back(t);
        if (val[t]==1) cnt++;
    }

    return count_common_roads(Q) - cnt;
}

std::vector<int> find_roads(int N, std::vector<int> u, std::vector<int> v) {
    if (N==2) return {0};
    n = N;
    U = u, V = v;
    fill(adj[0], adj[504]+505, -1);
    for (int i=0;i<(int)u.size();i++){
        adj[u[i]][v[i]] = i;
        adj[v[i]][u[i]] = i;
    }

    fill(val, val+100100, -1);
    fill(dfs_chk, dfs_chk+100100, 0);
    fill(visited, visited+505, 0);
    DV.clear();
    for (int i=0;i<505;i++) adj2[i].clear();
    dfs(0);
    int cnt0 = count_common_roads(DV);
    //for (auto &x:DV) printf("%d ", x);
    //printf("\n");
    int cntq = 0;

    for (int i=0;i<(int)u.size();i++) if (!dfs_chk[i]){
        E.clear();
        F.clear();
        fill(visited, visited+n, 0);
        assert(find_path(u[i], v[i]));
        //printf("%d: ", i);
        //for (auto &x:E) printf("%d ", x);
        //printf("\n");

        bool flag = 0, flag2 = 0;;
        for (auto &t:E) if (val[t]!=-1) flag = 1;
        for (auto &t:E) if (val[t]==-1) flag2 = 1;
        if (!flag2) continue;

        vector<int> Q = DV;
        int flag3 = -1, val2 = -1;
        int prvE = i;
        for (auto &t:E){
            if (flag3!=-1 && val[t]!=-1) {F.push_back(INF); continue;}
            for (auto iter = Q.begin();iter!=Q.end();iter++) if (*iter==t) {Q.erase(iter); break;}
            Q.push_back(prvE);
            F.push_back(count_common_roads(Q));
            cntq++;
            prvE = t;

            if (val[t]!=-1) flag3 = t, val2 = F.back();
        }

        if (!flag){
            int mn = min(*min_element(F.begin(), F.end()), cnt0);
            int mx = max(*max_element(F.begin(), F.end()), cnt0);
            for (int i=0;i<(int)F.size();i++){
                if (mn==mx) val[E[i]] = 0;
                else if (F[i]==mn) val[E[i]] = 1;
                else val[E[i]] = 0;
            }
        }
        else{
            assert(flag3!=-1);
            if (val[flag3]==0) val2--;
            //printf(" %d %d\n", flag3, val2);

            for (int i=0;i<(int)F.size();i++){
                //printf(" %d", F[i]);
                if (F[i]==val2) val[E[i]] = 1;
                else if (F[i]!=INF) val[E[i]] = 0;
            }
        }
        //for (int i=0;i<(int)u.size();i++) printf("%d ", val[i]);
        //printf("\n");
    }
    //printf("YES\n");
    assert(cntq<=n*2);

    for (int i=0;i<(int)DV.size();i++) if (val[DV[i]]==-1) val[DV[i]] = 1;
    //for (int i=0;i<(int)u.size();i++) printf("%d ", val[i]);
    //printf("\n");

    vector<int> ans;

    for (int i=0;i<n;i++){
        int prv = i;
        while(calc(i, prv+1, n-1) > 0){
            //printf(" %d %d\n", i, prv);
            int l = prv+1, r = n-1;
            while(r-l > 0){
                int m = (l+r)>>1;
                if (calc(i, l, m) > 0) r = m;
                else l = m+1;
            }
            ans.push_back(adj[i][l]);
            prv = l;
        }
    }
    //printf("ans: ");
    //for (auto &x:ans) printf("%d ", x);
    //printf("\n");

    //printf("YES:simurgh\n");

    if ((int)ans.size()!=n-1) exit(1);
    assert(count_common_roads(ans)==n-1);

    return ans;
}

• Subtask 1: 13 / 13
• Subtask 2: 17 / 17
• Subtask 3: 21 / 21
• Subtask 4: 0 / 19
• Subtask 5: 0 / 30