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답안 #237382

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
237382 2020-06-06T10:12:36 Z lyc Simurgh (IOI17_simurgh) C++14
100 / 100
 668 ms 13808 KB 
#include "simurgh.h"
#include <bits/stdc++.h>
using namespace std;

#define TRACE(x) cout << #x << " :: " << x << endl;
#define _ << " " <<
#define FOR(i,a,b) for(int i=(a);i<=(b);++i)
#define RFOR(i,a,b) for(int i=(a);i>=(b);--i)
#define SZ(x) ((int)(x).size())
#define ALL(x) (x).begin(),(x).end()
using vi = vector<int>;

const int mxN = 505;
const int mxM = (500*499)/2 + 10;
const int mxQ = 8000;
int N, M, q = 0;
int U[mxM], V[mxM];
vector<int> al[mxN];
vector<int> span;
int golden[mxM];

struct UnionFind {
    vector<int> pa, sz; int comp;
    UnionFind(int n) { pa.assign(n,0); iota(ALL(pa),0); sz.assign(n,0); comp = n;}
    int findset(int i) { return (i == pa[i]) ? i : (pa[i] = findset(pa[i])); }
    bool unionset(int i, int j) {
        int x = findset(i), y = findset(j);
        if (x != y) {
            --comp;
            if (sz[x] < sz[y]) swap(x,y);
            sz[x] += sz[y], pa[y] = x;
            return true;
        } return false;
    }
};

int ask(vector<int> edges, bool sub=false) {
    //assert(++q <= mxQ);
    UnionFind UF(N);
    for (int e : edges) {
        int u = U[e], v = V[e];
        assert(UF.unionset(u,v));
        UF.unionset(u,v);
    }
    int cnt = 0;
    for (int e : span) if (UF.unionset(U[e],V[e])) {
        edges.push_back(e);
        cnt += (golden[e] == 1);
    }
    //cout << "ASK: "; for (int e : edges) { cout << U[e] _ V[e] << ", "; } cout << endl;
    assert(UF.comp == 1);
    return count_common_roads(edges) - (sub ? cnt : 0);
}

int pa[mxN], pre[mxN], low[mxN], dfc, dfr;
vi ears[mxM];
int esz = 0;
vi* cur[mxN];
vector<vi*> decomp;
void dfs(int u, int p) {
    pre[u] = low[u] = dfc++;
    vector<vi*> vec;
    for (int e : al[u]) {
        int v = U[e]^V[e]^u;
        if (v == p) continue;
        if (pre[v] == -1) {
            pa[v] = e;
            dfs(v,u);
            span.push_back(e);
            if (low[v] > pre[u]) { // bridge
                golden[e] = 1;
                if (cur[v] != nullptr) decomp.push_back(cur[v]);
            } else {
                low[u] = min(low[u],low[v]);
                cur[v]->push_back(e);
                vec.push_back(cur[v]);
            }
        } else if (pre[v] < pre[u]) {
            low[u] = min(low[u],pre[v]);
            ears[esz] = {v,e};
            vec.push_back(&ears[esz++]);
        }
    }
    int fst = 0;
    cur[u] = nullptr;
    for (vi* x : vec) {
        int d = pre[*x->begin()];
        if (d > low[u] || (d == low[u] && ++fst > 1)) decomp.push_back(x);
        else cur[u] = x;
    }
    if (u == dfr && cur[u] != nullptr) decomp.push_back(cur[u]);
}

void solve(vi* ear) {
    //{cout << "EAR " << SZ(*ear) << ": ";
    //int u = *ear->begin();
    //bool fst = 1;
    //for (int e : (*ear)) {
    //    if (fst) fst = 0;
    //    else u ^= U[e]^V[e];
    //    cout << u << ' ';
    //}
    //cout << endl;}

    vector<int> x[2];
    int u = (*ear)[0], v = u, f = (*ear)[1];
    FOR(i,1,SZ(*ear)-1){
        int e = (*ear)[i];
        if (i > 1) x[golden[e] != -1].push_back(e);
        v ^= U[e]^V[e];
    }
    while (v != u) {
        x[golden[pa[v]] != -1].push_back(pa[v]);
        v ^= U[pa[v]]^V[pa[v]];
    }
    if (x[0].empty());
    else if (x[1].empty()) {
        vector<int> que;
        //cout << f << " CASE 1: ";
        //for (int& e : x[0]) cout << e << ": " << U[e] _ V[e] << ", ";
        //cout << endl;
        int mx = ask(x[0]);
        FOR(i,0,SZ(x[0])-1){
            //TRACE("ask" _ x[0][i] _ "without" _ U[x[0][i]] _ V[x[0][i]]);
            swap(x[0][i],f);
            int q = ask(x[0]);
            swap(x[0][i],f);
            que.push_back(q);
            mx = max(mx,q);
        }
        FOR(i,0,SZ(x[0])-1){
            //TRACE(i _ que[i] _ mx);
            golden[x[0][i]] = que[i] < mx; // removed decreases
        }
    } else {
        vector<int> edges(x[0]);
        FOR(i,1,SZ(x[1])-1) edges.push_back(x[1][i]);
        edges.push_back(f);
        //cout << f << " CASE 2: ";
        //for (int& e : x[0]) cout << e << ": " << U[e] _ V[e] << ", ";
        //cout << endl;
        int r = ask(edges);
        FOR(i,0,SZ(x[0])-1){
            swap(edges[i],x[1][0]);
            int q = ask(edges);
            swap(edges[i],x[1][0]);
            golden[x[0][i]] = ((golden[x[1][0]] && q == r) || q < r);
        }
    }
}

std::vector<int> find_roads(int n, std::vector<int> u, std::vector<int> v) {
    N = n;
    M = SZ(u);
    FOR(i,0,M-1){
        U[i] = u[i], V[i] = v[i];
        al[u[i]].push_back(i);
        al[v[i]].push_back(i);
    }

    fill(golden,golden+M,-1);
    fill(pre,pre+n,-1); dfc = dfr = 0;
    dfs(0,-1);

    for (vi* x : decomp) solve(x);
    //for (int& e : span) { TRACE(e _ ":" _ U[e] _ V[e] _ golden[e]); }

    FOR(i,0,N-1) {
        for (;;) {
            vector<int> all;
            for (int e : al[i]) if (golden[e] == -1) all.push_back(e);
            if (all.empty()) break;
            if (!ask(all,true)) {
                for (int e : all) golden[e] = 0;
                break;
            }
            int lo = -1, hi = SZ(all)-1;
            while (hi-lo > 1) {
                int mid = (lo+hi)/2;
                vector<int> edges;
                FOR(i,lo+1,mid) edges.push_back(all[i]);
                if (ask(edges,true)) hi = mid;
                else lo = mid;
            }
            golden[all[hi]] = 1;
        }
    }

    vector<int> ans;
    FOR(i,0,M-1) if (golden[i] == 1) ans.push_back(i);
	return ans;
}

Subtask #1
13.0 / 13.0

# 결과 실행 시간 메모리 Grader output
1 Correct 6 ms 3328 KB correct
2 Correct 6 ms 3328 KB correct
3 Correct 6 ms 3328 KB correct
4 Correct 6 ms 3328 KB correct
5 Correct 6 ms 3328 KB correct
6 Correct 6 ms 3328 KB correct
7 Correct 6 ms 3328 KB correct
8 Correct 6 ms 3328 KB correct
9 Correct 6 ms 3328 KB correct
10 Correct 6 ms 3328 KB correct
11 Correct 6 ms 3328 KB correct
12 Correct 6 ms 3328 KB correct
13 Correct 6 ms 3328 KB correct

Subtask #2
17.0 / 17.0

# 결과 실행 시간 메모리 Grader output
1 Correct 6 ms 3328 KB correct
2 Correct 6 ms 3328 KB correct
3 Correct 6 ms 3328 KB correct
4 Correct 6 ms 3328 KB correct
5 Correct 6 ms 3328 KB correct
6 Correct 6 ms 3328 KB correct
7 Correct 6 ms 3328 KB correct
8 Correct 6 ms 3328 KB correct
9 Correct 6 ms 3328 KB correct
10 Correct 6 ms 3328 KB correct
11 Correct 6 ms 3328 KB correct
12 Correct 6 ms 3328 KB correct
13 Correct 6 ms 3328 KB correct
14 Correct 9 ms 3456 KB correct
15 Correct 9 ms 3456 KB correct
16 Correct 8 ms 3456 KB correct
17 Correct 9 ms 3328 KB correct
18 Correct 7 ms 3328 KB correct
19 Correct 8 ms 3456 KB correct
20 Correct 8 ms 3328 KB correct
21 Correct 8 ms 3328 KB correct
22 Correct 7 ms 3328 KB correct
23 Correct 7 ms 3328 KB correct
24 Correct 7 ms 3328 KB correct
25 Correct 6 ms 3328 KB correct
26 Correct 7 ms 3328 KB correct
27 Correct 7 ms 3328 KB correct
28 Correct 7 ms 3328 KB correct
29 Correct 7 ms 3328 KB correct
30 Correct 7 ms 3328 KB correct
31 Correct 7 ms 3328 KB correct
32 Correct 8 ms 3328 KB correct
33 Correct 7 ms 3328 KB correct

Subtask #3
21.0 / 21.0

# 결과 실행 시간 메모리 Grader output
1 Correct 6 ms 3328 KB correct
2 Correct 6 ms 3328 KB correct
3 Correct 6 ms 3328 KB correct
4 Correct 6 ms 3328 KB correct
5 Correct 6 ms 3328 KB correct
6 Correct 6 ms 3328 KB correct
7 Correct 6 ms 3328 KB correct
8 Correct 6 ms 3328 KB correct
9 Correct 6 ms 3328 KB correct
10 Correct 6 ms 3328 KB correct
11 Correct 6 ms 3328 KB correct
12 Correct 6 ms 3328 KB correct
13 Correct 6 ms 3328 KB correct
14 Correct 9 ms 3456 KB correct
15 Correct 9 ms 3456 KB correct
16 Correct 8 ms 3456 KB correct
17 Correct 9 ms 3328 KB correct
18 Correct 7 ms 3328 KB correct
19 Correct 8 ms 3456 KB correct
20 Correct 8 ms 3328 KB correct
21 Correct 8 ms 3328 KB correct
22 Correct 7 ms 3328 KB correct
23 Correct 7 ms 3328 KB correct
24 Correct 7 ms 3328 KB correct
25 Correct 6 ms 3328 KB correct
26 Correct 7 ms 3328 KB correct
27 Correct 7 ms 3328 KB correct
28 Correct 7 ms 3328 KB correct
29 Correct 7 ms 3328 KB correct
30 Correct 7 ms 3328 KB correct
31 Correct 7 ms 3328 KB correct
32 Correct 8 ms 3328 KB correct
33 Correct 7 ms 3328 KB correct
34 Correct 97 ms 5756 KB correct
35 Correct 99 ms 5628 KB correct
36 Correct 77 ms 4992 KB correct
37 Correct 22 ms 3476 KB correct
38 Correct 99 ms 5628 KB correct
39 Correct 91 ms 5372 KB correct
40 Correct 75 ms 4992 KB correct
41 Correct 95 ms 5628 KB correct
42 Correct 94 ms 5628 KB correct
43 Correct 41 ms 4608 KB correct
44 Correct 35 ms 4352 KB correct
45 Correct 39 ms 4480 KB correct
46 Correct 34 ms 4224 KB correct
47 Correct 22 ms 3712 KB correct
48 Correct 11 ms 3328 KB correct
49 Correct 16 ms 3584 KB correct
50 Correct 21 ms 3832 KB correct
51 Correct 40 ms 4480 KB correct
52 Correct 35 ms 4352 KB correct
53 Correct 32 ms 4224 KB correct
54 Correct 41 ms 4608 KB correct
55 Correct 48 ms 4480 KB correct
56 Correct 49 ms 4488 KB correct
57 Correct 48 ms 4608 KB correct

Subtask #4
19.0 / 19.0

# 결과 실행 시간 메모리 Grader output
1 Correct 6 ms 3328 KB correct
2 Correct 6 ms 3328 KB correct
3 Correct 363 ms 10300 KB correct
4 Correct 644 ms 13804 KB correct
5 Correct 653 ms 13804 KB correct
6 Correct 625 ms 13804 KB correct
7 Correct 633 ms 13676 KB correct
8 Correct 631 ms 13804 KB correct
9 Correct 656 ms 13760 KB correct
10 Correct 658 ms 13676 KB correct
11 Correct 658 ms 13808 KB correct
12 Correct 662 ms 13724 KB correct
13 Correct 6 ms 3328 KB correct
14 Correct 639 ms 13676 KB correct
15 Correct 641 ms 13804 KB correct

Subtask #5
30.0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 6 ms 3328 KB correct
2 Correct 6 ms 3328 KB correct
3 Correct 6 ms 3328 KB correct
4 Correct 6 ms 3328 KB correct
5 Correct 6 ms 3328 KB correct
6 Correct 6 ms 3328 KB correct
7 Correct 6 ms 3328 KB correct
8 Correct 6 ms 3328 KB correct
9 Correct 6 ms 3328 KB correct
10 Correct 6 ms 3328 KB correct
11 Correct 6 ms 3328 KB correct
12 Correct 6 ms 3328 KB correct
13 Correct 6 ms 3328 KB correct
14 Correct 9 ms 3456 KB correct
15 Correct 9 ms 3456 KB correct
16 Correct 8 ms 3456 KB correct
17 Correct 9 ms 3328 KB correct
18 Correct 7 ms 3328 KB correct
19 Correct 8 ms 3456 KB correct
20 Correct 8 ms 3328 KB correct
21 Correct 8 ms 3328 KB correct
22 Correct 7 ms 3328 KB correct
23 Correct 7 ms 3328 KB correct
24 Correct 7 ms 3328 KB correct
25 Correct 6 ms 3328 KB correct
26 Correct 7 ms 3328 KB correct
27 Correct 7 ms 3328 KB correct
28 Correct 7 ms 3328 KB correct
29 Correct 7 ms 3328 KB correct
30 Correct 7 ms 3328 KB correct
31 Correct 7 ms 3328 KB correct
32 Correct 8 ms 3328 KB correct
33 Correct 7 ms 3328 KB correct
34 Correct 97 ms 5756 KB correct
35 Correct 99 ms 5628 KB correct
36 Correct 77 ms 4992 KB correct
37 Correct 22 ms 3476 KB correct
38 Correct 99 ms 5628 KB correct
39 Correct 91 ms 5372 KB correct
40 Correct 75 ms 4992 KB correct
41 Correct 95 ms 5628 KB correct
42 Correct 94 ms 5628 KB correct
43 Correct 41 ms 4608 KB correct
44 Correct 35 ms 4352 KB correct
45 Correct 39 ms 4480 KB correct
46 Correct 34 ms 4224 KB correct
47 Correct 22 ms 3712 KB correct
48 Correct 11 ms 3328 KB correct
49 Correct 16 ms 3584 KB correct
50 Correct 21 ms 3832 KB correct
51 Correct 40 ms 4480 KB correct
52 Correct 35 ms 4352 KB correct
53 Correct 32 ms 4224 KB correct
54 Correct 41 ms 4608 KB correct
55 Correct 48 ms 4480 KB correct
56 Correct 49 ms 4488 KB correct
57 Correct 48 ms 4608 KB correct
58 Correct 6 ms 3328 KB correct
59 Correct 6 ms 3328 KB correct
60 Correct 363 ms 10300 KB correct
61 Correct 644 ms 13804 KB correct
62 Correct 653 ms 13804 KB correct
63 Correct 625 ms 13804 KB correct
64 Correct 633 ms 13676 KB correct
65 Correct 631 ms 13804 KB correct
66 Correct 656 ms 13760 KB correct
67 Correct 658 ms 13676 KB correct
68 Correct 658 ms 13808 KB correct
69 Correct 662 ms 13724 KB correct
70 Correct 6 ms 3328 KB correct
71 Correct 639 ms 13676 KB correct
72 Correct 641 ms 13804 KB correct
73 Correct 6 ms 3328 KB correct
74 Correct 635 ms 13676 KB correct
75 Correct 615 ms 13492 KB correct
76 Correct 236 ms 7152 KB correct
77 Correct 646 ms 13712 KB correct
78 Correct 668 ms 13716 KB correct
79 Correct 665 ms 13676 KB correct
80 Correct 658 ms 13460 KB correct
81 Correct 528 ms 12012 KB correct
82 Correct 654 ms 13420 KB correct
83 Correct 391 ms 8656 KB correct
84 Correct 273 ms 9968 KB correct
85 Correct 237 ms 9072 KB correct
86 Correct 154 ms 7280 KB correct
87 Correct 111 ms 6140 KB correct
88 Correct 90 ms 5500 KB correct
89 Correct 95 ms 5372 KB correct
90 Correct 79 ms 4992 KB correct
91 Correct 40 ms 3456 KB correct
92 Correct 27 ms 3328 KB correct
93 Correct 218 ms 9072 KB correct
94 Correct 150 ms 7160 KB correct
95 Correct 145 ms 7200 KB correct
96 Correct 84 ms 5120 KB correct
97 Correct 95 ms 5500 KB correct
98 Correct 105 ms 6140 KB correct
99 Correct 91 ms 5500 KB correct
100 Correct 54 ms 3840 KB correct
101 Correct 30 ms 3456 KB correct
102 Correct 286 ms 8568 KB correct
103 Correct 306 ms 8688 KB correct
104 Correct 295 ms 8568 KB correct
105 Correct 295 ms 8568 KB correct