Submission #97356

#TimeUsernameProblemLanguageResultExecution timeMemory
97356E869120Highway Tolls (IOI18_highway)C++14
90 / 100
591 ms37792 KiB
#include "highway.h" #include <bits/stdc++.h> using namespace std; int N, M, U[1 << 18], V[1 << 18], dist[1 << 18], par[1 << 18], paredge[1 << 18]; vector<pair<int, int>> G[1 << 18]; bool anti[1 << 18]; vector<int> GG[1<<18]; int depth[1<<18], BB[1<<18]; map<pair<int, int>, int>MM; void dfs(int pos, int dep) { depth[pos] = dep; for (int i = 0; i < GG[pos].size(); i++) { if(depth[GG[pos][i]] != -1) continue; par[GG[pos][i]] = pos; BB[GG[pos][i]] = MM[make_pair(GG[pos][i], pos)]; dfs(GG[pos][i], dep + 1); } } void find_pair(int NN, vector<int> UU, vector<int> VV, int A, int B) { if (NN - 1 == (int)UU.size()) { N = NN; for (int i = 0; i < UU.size(); i++) { GG[UU[i]].push_back(VV[i]); GG[VV[i]].push_back(UU[i]); MM[make_pair(UU[i], VV[i])] = i; MM[make_pair(VV[i], UU[i])] = i; } for (int i = 0; i < N; i++) depth[i] = -1; dfs(0, 0); vector<int> W(N - 1, 0); for (int i = 0; i < N - 1; i++) W[i] = 0; long long c1 = ask(W); for (int i = 0; i < N - 1; i++) W[i] = 1; long long c2 = ask(W); vector<pair<int, int>> T; for (int i = 1; i < N; i++) T.push_back(make_pair(depth[i], i)); sort(T.begin(), T.end()); // Part 1. Find the lowest int L1 = 0, R1 = N - 1, M1, ret1 = 0; for (int i = 0; i < 19; i++) { M1 = (L1 + R1) / 2; for (int j = 0; j < T.size(); j++) { if (j < M1) W[BB[T[j].second]] = 0; else W[BB[T[j].second]] = 1; } long long c3 = ask(W); if (c1 == c3) { R1 = M1; } else { L1 = M1; ret1 = max(ret1, M1); } } int cx = T[ret1].second; while (true) { anti[cx] = true; if (cx == 0) break; cx = par[cx]; } // Part 2. Find the highest int L2 = 0, R2 = N - 1, M2, ret2 = N - 2; for (int i = 0; i < 19; i++) { M2 = (L2 + R2) / 2; for (int j = 0; j < T.size(); j++) { if (j <= M2) W[BB[T[j].second]] = 1; else W[BB[T[j].second]] = 0; } long long c3 = ask(W); if (c1 == c3) { L2 = M2; } else { R2 = M2; ret2 = min(ret2, M2); } } // Part 3. Find the second long long P1 = T[ret1].first, P2 = T[ret2].first - 1, Leng = (c2 - c1) / (1LL * B - 1LL * A); long long P3 = P2 + (Leng - (P1 - P2)); if (P3 == P2) { answer(par[T[ret2].second], T[ret1].second); return; } vector<int>I; for (int i = 0; i < N; i++) { if (depth[i] == P3 && anti[i] == false) { I.push_back(i); } } int L3 = 0, R3 = I.size(), M3, ret3 = I.size() - 1; for (int i = 0; i < 19; i++) { M3 = (L3 + R3) / 2; for (int j = 0; j < N; j++) W[j] = 0; for (int j = 0; j <= M3; j++) W[BB[I[j]]] = 1; long long c3 = ask(W); if (c1 == c3) { L3 = M3; } else { R3 = M3; ret3 = min(ret3, M3); } } answer(I[ret3], T[ret1].second); return; } // ----------------------------- Step 0: Input --------------------------- N = NN; M = UU.size(); for (int i = 0; i < M; i++) { U[i] = UU[i]; V[i] = VV[i]; } // -------------------------- Step 1: Get All-A -------------------------- vector<int> W(M, 0); long long BASE = ask(W), DIST = BASE / A; // ---------------------- Step 2: The Minimum Vertex --------------------- int c1 = 0; for (int i = 16; i >= 0; i--) { for (int j = 0; j < M; j++) { if (min(U[j], V[j]) >= c1 + (1 << i)) W[j] = 0; else W[j] = 1; } long long p1 = ask(W); if (p1 == BASE) { c1 += (1 << i); } } // -------------------------- Step 3: Make Tree -------------------------- for (int i = 0; i < M; i++) { if (min(U[i], V[i]) < c1) continue; G[U[i]].push_back(make_pair(V[i], i)); G[V[i]].push_back(make_pair(U[i], i)); } for (int i = 0; i < N; i++) dist[i] = (1 << 30); queue<int> que; que.push(c1); dist[c1] = 0; while (!que.empty()) { int pos1 = que.front(); que.pop(); for (int i = 0; i < G[pos1].size(); i++) { int to = G[pos1][i].first; if (dist[to] > dist[pos1] + 1) { dist[to] = dist[pos1] + 1; que.push(to); } } } for (int i = c1 + 1; i < N; i++) { for (int j = 0; j < G[i].size(); j++) { int to = G[i][j].first; if (dist[i] > dist[to]) { par[i] = to; paredge[i] = G[i][j].second; break; } } } // ---------------------------- 4. Find T -------------------------------- vector<pair<int, int>> V; for (int i = c1 + 1; i < N; i++) { if (dist[i] == (1 << 30)) continue; V.push_back(make_pair(dist[i], i)); } sort(V.begin(), V.end()); //for (int i = 0; i < V.size(); i++) cout << "V[" << i << "] = " << V[i].second << endl; int c2 = 0; for (int i = 16; i >= 0; i--) { for (int j = 0; j < W.size(); j++) W[j] = 1; for (int j = 0; j < c2 + (1 << i); j++) { if (j >= V.size()) break; W[paredge[V[j].second]] = 0; } long long p2 = ask(W); if (p2 != BASE) c2 += (1 << i); } // --------------------- 5. Find the candidate of S ---------------------- long long T = V[c2].second, cand_dst = DIST - dist[T]; if (cand_dst == 0) { answer(T, c1); return; } int cx = T; anti[cx] = true; while (true) { cx = par[cx]; anti[cx] = true; if (cx == c1) break; } vector<int> V2; for (int i = c1 + 1; i < N; i++) { if (dist[i] == cand_dst && anti[i] == false) V2.push_back(i); } // ----------------------------- 6. Find S -------------------------------- int c3 = 0; for (int i = 16; i >= 0; i--) { for (int j = 0; j < W.size(); j++) W[j] = 1; for (int j = c1 + 1; j < W.size(); j++) W[paredge[j]] = 0; for (int j = 0; j < c3 + (1 << i); j++) { if (j >= V2.size()) break; W[paredge[V2[j]]] = 1; } long long p3 = ask(W); if (p3 == BASE) c3 += (1 << i); } long long S = V2[c3]; answer(S, T); return; }

Compilation message (stderr)

highway.cpp: In function 'void dfs(int, int)':
highway.cpp:13:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < GG[pos].size(); i++) {
                  ~~^~~~~~~~~~~~~~~~
highway.cpp: In function 'void find_pair(int, std::vector<int>, std::vector<int>, int, int)':
highway.cpp:24:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i = 0; i < UU.size(); i++) {
                   ~~^~~~~~~~~~~
highway.cpp:33:3: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
   for (int i = 0; i < N - 1; i++) W[i] = 0; long long c1 = ask(W);
   ^~~
highway.cpp:33:45: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
   for (int i = 0; i < N - 1; i++) W[i] = 0; long long c1 = ask(W);
                                             ^~~~
highway.cpp:34:3: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
   for (int i = 0; i < N - 1; i++) W[i] = 1; long long c2 = ask(W);
   ^~~
highway.cpp:34:45: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
   for (int i = 0; i < N - 1; i++) W[i] = 1; long long c2 = ask(W);
                                             ^~~~
highway.cpp:44:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for (int j = 0; j < T.size(); j++) { if (j < M1) W[BB[T[j].second]] = 0; else W[BB[T[j].second]] = 1; }
                    ~~^~~~~~~~~~
highway.cpp:60:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for (int j = 0; j < T.size(); j++) { if (j <= M2) W[BB[T[j].second]] = 1; else W[BB[T[j].second]] = 0; }
                    ~~^~~~~~~~~~
highway.cpp:126:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i = 0; i < G[pos1].size(); i++) {
                   ~~^~~~~~~~~~~~~~~~
highway.cpp:136:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int j = 0; j < G[i].size(); j++) {
                   ~~^~~~~~~~~~~~~
highway.cpp:154:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int j = 0; j < W.size(); j++) W[j] = 1;
                   ~~^~~~~~~~~~
highway.cpp:156:10: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    if (j >= V.size()) break;
        ~~^~~~~~~~~~~
highway.cpp:185:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int j = 0; j < W.size(); j++) W[j] = 1;
                   ~~^~~~~~~~~~
highway.cpp:186:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int j = c1 + 1; j < W.size(); j++) W[paredge[j]] = 0;
                        ~~^~~~~~~~~~
highway.cpp:189:10: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    if (j >= V2.size()) break;
        ~~^~~~~~~~~~~~
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