Submission #8533657
Source Code Expand
#include<bits/stdc++.h> using namespace std; #define rep(i, a, b) for(int i = a; i < (b); ++i) #define trav(a, x) for(auto& a : x) #define all(x) begin(x), end(x) #define sz(x) (int)(x).size() typedef long long ll; typedef pair<int, int> pii; typedef vector<int> vi; bool dfs(int a, int L, vector<vi>& g, vi& btoa, vi& A, vi& B) { if (A[a] != L) return 0; A[a] = -1; trav(b, g[a]) if (B[b] == L + 1) { B[b] = 0; if (btoa[b] == -1 || dfs(btoa[b], L + 1, g, btoa, A, B)) return btoa[b] = a, 1; } return 0; } int hopcroftKarp(vector<vi>& g, vi& btoa) { int res = 0; vi A(g.size()), B(btoa.size()), cur, next; for (;;) { fill(all(A), 0); fill(all(B), 0); /// Find the starting nodes for BFS (i.e. layer 0). cur.clear(); trav(a, btoa) if(a != -1) A[a] = -1; rep(a,0,sz(g)) if(A[a] == 0) cur.push_back(a); /// Find all layers using bfs. for (int lay = 1;; lay++) { bool islast = 0; next.clear(); trav(a, cur) trav(b, g[a]) { if (btoa[b] == -1) { B[b] = lay; islast = 1; } else if (btoa[b] != a && !B[b]) { B[b] = lay; next.push_back(btoa[b]); } } if (islast) break; if (next.empty()) return res; trav(a, next) A[a] = lay; cur.swap(next); } /// Use DFS to scan for augmenting paths. rep(a,0,sz(g)) res += dfs(a, 0, g, btoa, A, B); } } const int V = 1.1e7; bool isPrime[V + 1]; int main() { ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0); for (int i = 2; i <= V; i++) isPrime[i] = true; for (int p = 2; p <= V; p++) { if (!isPrime[p]) continue; for (int j = p+p; j <= V; j += p) isPrime[j] = false; } int N; cin >> N; vector<int> X(N); map<int, int> evtCnt; for (int i = 0; i < N; i++) { cin >> X[i]; evtCnt[X[i]] ^= 1; evtCnt[X[i]+1] ^= 1; } vector<int> left; vector<int> right; for (auto it : evtCnt) { if (it.second == 0) continue; if (it.first & 1) right.push_back(it.first); else left.push_back(it.first); } int A = int(left.size()); int B = int(right.size()); vector<vector<int>> g(A); vector<int> btoa(B, -1); isPrime[2] = false; for (int i = 0; i < A; i++) { for (int j = 0; j < B; j++) { if (isPrime[abs(left[i] - right[j])]) { g[i].push_back(j); } } } int ans = hopcroftKarp(g, btoa); // number that can be paired cerr << ans << ' ' << A << ' ' << B << '\n'; A -= ans, B -= ans; cout << ans + (A/2) * 2 + (B/2) * 2 + (A % 2 ? 3 : 0) << '\n'; return 0; }
Submission Info
Submission Time | |
---|---|
Task | F - Prime Flip |
User | ecnerwala |
Language | C++14 (GCC 5.4.1) |
Score | 1200 |
Code Size | 2532 Byte |
Status | AC |
Exec Time | 86 ms |
Memory | 11008 KB |
Judge Result
Set Name | Sample | All | ||||
---|---|---|---|---|---|---|
Score / Max Score | 0 / 0 | 1200 / 1200 | ||||
Status |
|
|
Set Name | Test Cases |
---|---|
Sample | 0_00.txt, 0_01.txt, 0_02.txt |
All | 0_00.txt, 0_01.txt, 0_02.txt, 1_00.txt, 1_01.txt, 1_02.txt, 1_03.txt, 1_04.txt, 1_05.txt, 1_06.txt, 1_07.txt, 1_08.txt, 1_09.txt, 1_10.txt, 1_11.txt, 1_12.txt, 1_13.txt, 1_14.txt, 1_15.txt, 1_16.txt, 1_17.txt, 1_18.txt, 1_19.txt, 1_20.txt, 1_21.txt, 1_22.txt, 1_23.txt, 1_24.txt, 1_25.txt, 1_26.txt, 1_27.txt, 1_28.txt, 1_29.txt, 1_30.txt, 1_31.txt, 1_32.txt, 1_33.txt, 1_34.txt, 1_35.txt, 1_36.txt, 1_37.txt, 1_38.txt, 1_39.txt, 1_40.txt, 1_41.txt, 1_42.txt, 1_43.txt, 1_44.txt, 1_45.txt, 1_46.txt, 1_47.txt, 1_48.txt, 1_49.txt, 1_50.txt, 1_51.txt, 1_52.txt, 1_53.txt, 1_54.txt, 1_55.txt, 1_56.txt, 1_57.txt, 1_58.txt, 1_59.txt, 1_60.txt, 1_61.txt, 1_62.txt, 1_63.txt, 1_64.txt, 1_65.txt, 1_66.txt, 1_67.txt, 1_68.txt, 1_69.txt, 1_70.txt, 1_71.txt |
Case Name | Status | Exec Time | Memory |
---|---|---|---|
0_00.txt | AC | 81 ms | 11008 KB |
0_01.txt | AC | 81 ms | 11008 KB |
0_02.txt | AC | 81 ms | 11008 KB |
1_00.txt | AC | 81 ms | 11008 KB |
1_01.txt | AC | 81 ms | 11008 KB |
1_02.txt | AC | 81 ms | 11008 KB |
1_03.txt | AC | 81 ms | 11008 KB |
1_04.txt | AC | 81 ms | 11008 KB |
1_05.txt | AC | 81 ms | 11008 KB |
1_06.txt | AC | 80 ms | 11008 KB |
1_07.txt | AC | 81 ms | 11008 KB |
1_08.txt | AC | 81 ms | 11008 KB |
1_09.txt | AC | 81 ms | 11008 KB |
1_10.txt | AC | 81 ms | 11008 KB |
1_11.txt | AC | 81 ms | 11008 KB |
1_12.txt | AC | 81 ms | 11008 KB |
1_13.txt | AC | 81 ms | 11008 KB |
1_14.txt | AC | 81 ms | 11008 KB |
1_15.txt | AC | 81 ms | 11008 KB |
1_16.txt | AC | 81 ms | 11008 KB |
1_17.txt | AC | 81 ms | 11008 KB |
1_18.txt | AC | 81 ms | 11008 KB |
1_19.txt | AC | 81 ms | 11008 KB |
1_20.txt | AC | 81 ms | 11008 KB |
1_21.txt | AC | 81 ms | 11008 KB |
1_22.txt | AC | 81 ms | 11008 KB |
1_23.txt | AC | 81 ms | 11008 KB |
1_24.txt | AC | 82 ms | 11008 KB |
1_25.txt | AC | 86 ms | 11008 KB |
1_26.txt | AC | 81 ms | 11008 KB |
1_27.txt | AC | 81 ms | 11008 KB |
1_28.txt | AC | 81 ms | 11008 KB |
1_29.txt | AC | 81 ms | 11008 KB |
1_30.txt | AC | 81 ms | 11008 KB |
1_31.txt | AC | 81 ms | 11008 KB |
1_32.txt | AC | 83 ms | 11008 KB |
1_33.txt | AC | 80 ms | 11008 KB |
1_34.txt | AC | 81 ms | 11008 KB |
1_35.txt | AC | 82 ms | 11008 KB |
1_36.txt | AC | 81 ms | 11008 KB |
1_37.txt | AC | 83 ms | 11008 KB |
1_38.txt | AC | 81 ms | 11008 KB |
1_39.txt | AC | 81 ms | 11008 KB |
1_40.txt | AC | 81 ms | 11008 KB |
1_41.txt | AC | 81 ms | 11008 KB |
1_42.txt | AC | 81 ms | 11008 KB |
1_43.txt | AC | 82 ms | 11008 KB |
1_44.txt | AC | 81 ms | 11008 KB |
1_45.txt | AC | 81 ms | 11008 KB |
1_46.txt | AC | 81 ms | 11008 KB |
1_47.txt | AC | 81 ms | 11008 KB |
1_48.txt | AC | 81 ms | 11008 KB |
1_49.txt | AC | 83 ms | 11008 KB |
1_50.txt | AC | 81 ms | 11008 KB |
1_51.txt | AC | 81 ms | 11008 KB |
1_52.txt | AC | 81 ms | 11008 KB |
1_53.txt | AC | 81 ms | 11008 KB |
1_54.txt | AC | 81 ms | 11008 KB |
1_55.txt | AC | 81 ms | 11008 KB |
1_56.txt | AC | 81 ms | 11008 KB |
1_57.txt | AC | 84 ms | 11008 KB |
1_58.txt | AC | 80 ms | 11008 KB |
1_59.txt | AC | 81 ms | 11008 KB |
1_60.txt | AC | 80 ms | 11008 KB |
1_61.txt | AC | 81 ms | 11008 KB |
1_62.txt | AC | 83 ms | 11008 KB |
1_63.txt | AC | 82 ms | 11008 KB |
1_64.txt | AC | 80 ms | 11008 KB |
1_65.txt | AC | 81 ms | 11008 KB |
1_66.txt | AC | 80 ms | 11008 KB |
1_67.txt | AC | 80 ms | 11008 KB |
1_68.txt | AC | 80 ms | 11008 KB |
1_69.txt | AC | 80 ms | 11008 KB |
1_70.txt | AC | 81 ms | 11008 KB |
1_71.txt | AC | 80 ms | 11008 KB |