#include "sabotaz.h" #include "message.h" #include <algorithm> #include <iostream> #include <vector> using namespace std; const int N = 200001; vector<pair<int, bool> > g[N]; int d[N]; int low[N]; int par[N]; int n, m; void clear() { for(int i = 1; i <= n; i++) { g[i].clear(); d[i] = low[i] = 0; } } void buildGraph(const vector<int> &father) { for(int i = 0; i < n; i++) if(father[i] < 0) { g[i+1].emplace_back(-father[i], true); g[-father[i]].emplace_back(i+1, true); } else if(father[i] > 0) { g[i+1].emplace_back(father[i], false); g[father[i]].emplace_back(i+1, false); } } void dfs(int v, int prev) { low[v] = d[v] = d[prev] + 1; par[v] = prev; bool firstPrev = true; for(auto u: g[v]) if(u.first == prev && firstPrev && !u.second) firstPrev = false; else if(d[u.first]) low[v] = min(low[v], d[u.first]); else { dfs(u.first, v); low[v] = min(low[v], low[u.first]); } } vector<int> solve() { for(int i = 1; i <= n; i++) if(!d[i]) dfs(i, 0); vector<int> ans; ans.reserve(n); for(int i = 1; i <= n; i++) if(low[i] == d[i]) ans.push_back(par[i]); else ans.push_back(-par[i]); return ans; } const int MAXSIZE = 20000; void send(const vector<int> &vec, int target) { for(int i = 0; i < n; i += MAXSIZE) { for(int j = 0; j < MAXSIZE && i + j < n; j++) PutInt(target, vec[i+j]); Send(target); } } vector<int> receive(int target) { vector<int> ans(n); for(int i = 0; i < n; i += MAXSIZE) { Receive(target); for(int j = 0; j < MAXSIZE && i + j < n; j++) ans[i+j] = GetInt(target); } return ans; } int main() { n = NumberOfIsles(); m = NumberOfBridges(); int nodes = NumberOfNodes(), id = MyNodeId(); int block = (m + nodes - 1) / nodes; int start = id * block; for(int i = start; i < start + block && i < m; i++) { int a = BridgeEndA(i) + 1, b = BridgeEndB(i) + 1; g[a].emplace_back(b, false); g[b].emplace_back(a, false); } auto vec = solve(); int k = 1; while(true) { int s = id ^ k; if(s < id) { send(vec, s); return 0; } if(s < nodes) { auto vec2 = receive(s); clear(); buildGraph(vec); buildGraph(vec2); vec = solve(); } else if(id == 0) { int ans = 0; for(int x: vec) if(x > 0) ans++; printf("%d\n", ans); return 0; } k <<= 1; } }
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 | #include "sabotaz.h" #include "message.h" #include <algorithm> #include <iostream> #include <vector> using namespace std; const int N = 200001; vector<pair<int, bool> > g[N]; int d[N]; int low[N]; int par[N]; int n, m; void clear() { for(int i = 1; i <= n; i++) { g[i].clear(); d[i] = low[i] = 0; } } void buildGraph(const vector<int> &father) { for(int i = 0; i < n; i++) if(father[i] < 0) { g[i+1].emplace_back(-father[i], true); g[-father[i]].emplace_back(i+1, true); } else if(father[i] > 0) { g[i+1].emplace_back(father[i], false); g[father[i]].emplace_back(i+1, false); } } void dfs(int v, int prev) { low[v] = d[v] = d[prev] + 1; par[v] = prev; bool firstPrev = true; for(auto u: g[v]) if(u.first == prev && firstPrev && !u.second) firstPrev = false; else if(d[u.first]) low[v] = min(low[v], d[u.first]); else { dfs(u.first, v); low[v] = min(low[v], low[u.first]); } } vector<int> solve() { for(int i = 1; i <= n; i++) if(!d[i]) dfs(i, 0); vector<int> ans; ans.reserve(n); for(int i = 1; i <= n; i++) if(low[i] == d[i]) ans.push_back(par[i]); else ans.push_back(-par[i]); return ans; } const int MAXSIZE = 20000; void send(const vector<int> &vec, int target) { for(int i = 0; i < n; i += MAXSIZE) { for(int j = 0; j < MAXSIZE && i + j < n; j++) PutInt(target, vec[i+j]); Send(target); } } vector<int> receive(int target) { vector<int> ans(n); for(int i = 0; i < n; i += MAXSIZE) { Receive(target); for(int j = 0; j < MAXSIZE && i + j < n; j++) ans[i+j] = GetInt(target); } return ans; } int main() { n = NumberOfIsles(); m = NumberOfBridges(); int nodes = NumberOfNodes(), id = MyNodeId(); int block = (m + nodes - 1) / nodes; int start = id * block; for(int i = start; i < start + block && i < m; i++) { int a = BridgeEndA(i) + 1, b = BridgeEndB(i) + 1; g[a].emplace_back(b, false); g[b].emplace_back(a, false); } auto vec = solve(); int k = 1; while(true) { int s = id ^ k; if(s < id) { send(vec, s); return 0; } if(s < nodes) { auto vec2 = receive(s); clear(); buildGraph(vec); buildGraph(vec2); vec = solve(); } else if(id == 0) { int ans = 0; for(int x: vec) if(x > 0) ans++; printf("%d\n", ans); return 0; } k <<= 1; } } |