#include <bits/stdc++.h> using namespace std; #define endl "\n" #define mp make_pair #define st first #define nd second #define pii pair<int, int> #define vi vector<int> #define pb push_back #define _upgrade ios_base::sync_with_stdio(0), cout.setf(ios::fixed), cout.precision(10), cin.tie(0), cout.tie(0); #define rep(i, n) for (int i = 0; i < (n); ++i) #define fwd(i, a, b) for (int i = (a); i < (b); ++i) #define trav(a, x) for (auto &a : x) #define all(c) (c).begin(), (c).end() #define sz(X) (int)((X).size()) typedef long double ld; typedef unsigned long long ull; typedef long long ll; #ifdef LOCAL ostream &operator<<(ostream &out, string str) { for (char c : str) out << c; return out; } template <class L, class R> ostream &operator<<(ostream &out, pair<L, R> p) { return out << "(" << p.st << ", " << p.nd << ")"; } template <class L, class R, class S> ostream &operator<<(ostream &out, tuple<L, R, S> p) { auto &[a, b, c] = p; return out << "(" << a << ", " << b << ", " << c << ")"; } template <class T> auto operator<<(ostream &out, T a) -> decltype(a.begin(), out) { out << '{'; for (auto it = a.begin(); it != a.end(); it = next(it)) out << (it != a.begin() ? ", " : "") << *it; return out << '}'; } void dump() { cerr << "\n"; } template <class T, class... Ts> void dump(T a, Ts... x) { cerr << a << ", "; dump(x...); } #define debug(...) cerr << "[" #__VA_ARGS__ "]: ", dump(__VA_ARGS__) #else #define debug(...) 42 #endif #define int long long const int MAXA = 1e5 + 2; const int MAXB = 1e4 + 2; static_assert(MAXA * MAXB > 1e9); void dfs1(int x, int val, auto &G, auto &visited, auto &P) { if (val >= MAXA or val > P[x] or visited[x][val]) return; visited[x][val] = true; for (auto [y, w] : G[x]) dfs1(y, val * w, G, visited, P); } auto first_part(int n, auto &G, auto &P) { vector<array<bool, MAXA>> visited(n); dfs1(0, 1, G, visited, P); vector<vector<int>> res(n); rep(i, n) rep(t, sz(visited[i])) if (visited[i][t]) res[i].push_back(t); return res; } auto second_part(int n, auto &G, auto &P) { typedef array<int, 3> tpl; priority_queue<tpl> Q; vector<array<int, MAXB>> best(n); rep(i, n) rep(j, sz(best[i])) best[i][j] = -1; Q.push({P[n - 1], 1, n - 1}); while (!Q.empty()) { auto [p, w, x] = Q.top(); Q.pop(); if (best[x][w] != -1) { assert(best[x][w] >= p); continue; } assert(w <= MAXB); best[x][w] = p; for (auto [y, edge_w] : G[x]) { auto new_p = min(P[y], p / edge_w); auto new_w = edge_w * w; if (new_w >= MAXB) continue; Q.push({new_p, new_w, y}); } } return best; } void solve(int z) { int n, m; cin >> n >> m; vector<int> P(n); vector<vector<pii>> G(n), Gr(n); rep(i, n) cin >> P[i]; rep(i, m) { int a, b, w; cin >> a >> b >> w; G[--a].push_back({--b, w}); Gr[b].push_back({a, w}); } auto F = first_part(n, G, P); auto S = second_part(n, Gr, P); int res = n == 1 ? 1 : -1; rep(x, n) for (auto [y, edge_w] : Gr[x]) rep(j, sz(S[x])) if (auto max_pref = S[x][j]; max_pref != -1) { max_pref /= edge_w; auto itr = upper_bound(all(F[y]), max_pref); if (itr == F[y].begin()) continue; int first_part_w = *(--itr); int second_part_w = j; res = max(res, first_part_w * second_part_w * edge_w); } cout << res << endl; } int32_t main() { _upgrade; int Z; cin >> Z; rep(z, Z) { solve(z); // cerr << Z << endl; } }
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 | #include <bits/stdc++.h> using namespace std; #define endl "\n" #define mp make_pair #define st first #define nd second #define pii pair<int, int> #define vi vector<int> #define pb push_back #define _upgrade ios_base::sync_with_stdio(0), cout.setf(ios::fixed), cout.precision(10), cin.tie(0), cout.tie(0); #define rep(i, n) for (int i = 0; i < (n); ++i) #define fwd(i, a, b) for (int i = (a); i < (b); ++i) #define trav(a, x) for (auto &a : x) #define all(c) (c).begin(), (c).end() #define sz(X) (int)((X).size()) typedef long double ld; typedef unsigned long long ull; typedef long long ll; #ifdef LOCAL ostream &operator<<(ostream &out, string str) { for (char c : str) out << c; return out; } template <class L, class R> ostream &operator<<(ostream &out, pair<L, R> p) { return out << "(" << p.st << ", " << p.nd << ")"; } template <class L, class R, class S> ostream &operator<<(ostream &out, tuple<L, R, S> p) { auto &[a, b, c] = p; return out << "(" << a << ", " << b << ", " << c << ")"; } template <class T> auto operator<<(ostream &out, T a) -> decltype(a.begin(), out) { out << '{'; for (auto it = a.begin(); it != a.end(); it = next(it)) out << (it != a.begin() ? ", " : "") << *it; return out << '}'; } void dump() { cerr << "\n"; } template <class T, class... Ts> void dump(T a, Ts... x) { cerr << a << ", "; dump(x...); } #define debug(...) cerr << "[" #__VA_ARGS__ "]: ", dump(__VA_ARGS__) #else #define debug(...) 42 #endif #define int long long const int MAXA = 1e5 + 2; const int MAXB = 1e4 + 2; static_assert(MAXA * MAXB > 1e9); void dfs1(int x, int val, auto &G, auto &visited, auto &P) { if (val >= MAXA or val > P[x] or visited[x][val]) return; visited[x][val] = true; for (auto [y, w] : G[x]) dfs1(y, val * w, G, visited, P); } auto first_part(int n, auto &G, auto &P) { vector<array<bool, MAXA>> visited(n); dfs1(0, 1, G, visited, P); vector<vector<int>> res(n); rep(i, n) rep(t, sz(visited[i])) if (visited[i][t]) res[i].push_back(t); return res; } auto second_part(int n, auto &G, auto &P) { typedef array<int, 3> tpl; priority_queue<tpl> Q; vector<array<int, MAXB>> best(n); rep(i, n) rep(j, sz(best[i])) best[i][j] = -1; Q.push({P[n - 1], 1, n - 1}); while (!Q.empty()) { auto [p, w, x] = Q.top(); Q.pop(); if (best[x][w] != -1) { assert(best[x][w] >= p); continue; } assert(w <= MAXB); best[x][w] = p; for (auto [y, edge_w] : G[x]) { auto new_p = min(P[y], p / edge_w); auto new_w = edge_w * w; if (new_w >= MAXB) continue; Q.push({new_p, new_w, y}); } } return best; } void solve(int z) { int n, m; cin >> n >> m; vector<int> P(n); vector<vector<pii>> G(n), Gr(n); rep(i, n) cin >> P[i]; rep(i, m) { int a, b, w; cin >> a >> b >> w; G[--a].push_back({--b, w}); Gr[b].push_back({a, w}); } auto F = first_part(n, G, P); auto S = second_part(n, Gr, P); int res = n == 1 ? 1 : -1; rep(x, n) for (auto [y, edge_w] : Gr[x]) rep(j, sz(S[x])) if (auto max_pref = S[x][j]; max_pref != -1) { max_pref /= edge_w; auto itr = upper_bound(all(F[y]), max_pref); if (itr == F[y].begin()) continue; int first_part_w = *(--itr); int second_part_w = j; res = max(res, first_part_w * second_part_w * edge_w); } cout << res << endl; } int32_t main() { _upgrade; int Z; cin >> Z; rep(z, Z) { solve(z); // cerr << Z << endl; } } |