Submission #380289

#TimeUsernameProblemLanguageResultExecution timeMemory
380289fishy15Wild Boar (JOI18_wild_boar)C++17
0 / 100
18079 ms72428 KiB
#include <iostream> #include <iomanip> #include <fstream> #include <vector> #include <array> #include <algorithm> #include <utility> #include <map> #include <queue> #include <set> #include <cmath> #include <cstdio> #include <cstring> #define ll long long #define ld long double #define eps 1e-8 #define MOD 1000000007 #define INF 0x3f3f3f3f #define INFLL 0x3f3f3f3f3f3f3f3f // change if necessary #define MAXN 1010 #define MAXL 100010 using namespace std; struct path { int start, end; ll length; path(int s, int e, ll l) : start(s), end(e), length(l) {} path() : path(0, 0, 0) {} }; struct min_cost { path min[4]; // min, first diff, second diff, both diff bool set[4]; min_cost() { memset(set, 0, sizeof set); } }; int n, m, t, l; int nums[MAXL]; min_cost min_dist[MAXN][MAXN]; vector<int> adj[MAXN]; vector<pair<int, ll>> edge; bool same(int x, int y) { return x == y || (x ^ 1) == y; } // segtree stuff struct segtree { struct node { int l, r, sz; vector<path> combo; node(int l, int r, int sz) : l(l), r(r), sz(sz) {} node() : node(0, 0, 0) {} int size() const { return r - l + 1; } }; static int n; node st[4 * MAXN]; // i have no clue why this works but if i set T = path[4] // then it is passed as a pointer instead of an array // so i am doing this instead template<class T> void combo(node &ans, const vector<path> &left, const T &right) { map<pair<int, int>, ll> m; for (auto &p1 : left) { for (auto &p2 : right) { if (same(p1.end, p2.start) || p2.length == 0) continue; pair<int, int> pp = {p1.start, p2.end}; if (!m.count(pp)) { m[pp] = p1.length + p2.length; } else { m[pp] = min(m[pp], p1.length + p2.length); } } } for (auto p : m) { ans.combo.emplace_back(p.first.first, p.first.second, p.second); } } void combo(node &ans, const vector<path> &left, const vector<path> &right, int x1, int x2) { map<pair<int, int>, ll> m; for (auto &p1 : left) { for (auto &p2 : right) { for (auto &join : min_dist[x1][x2].min) { if (same(p1.end, join.start) || same(join.end, p2.start) || join.length == 0) continue; pair<int, int> pp = {p1.start, p2.end}; if (!m.count(pp)) { m[pp] = p1.length + p2.length + join.length; } else { m[pp] = min(m[pp], p1.length + p2.length + join.length); } } } } for (auto p : m) { ans.combo.emplace_back(p.first.first, p.first.second, p.second); } } node merge(const node &left, const node &right) { node ans; ans.l = left.l; ans.r = right.r; if (left.size() == 1) { for (path &p : min_dist[left.l][right.r].min) { if (p.length > 0) { ans.combo.push_back(p); } } return ans; } if (right.size() == 1) { combo<path[4]>(ans, left.combo, min_dist[left.r][right.l].min); } else { combo(ans, left.combo, right.combo, left.r, right.l); } return ans; } void build(int v = 1, int l = 0, int r = n - 1) { if (l == r) { st[v] = node(nums[l], nums[l], 1); } else { int m = (l + r) / 2; build(2 * v, l, m); build(2 * v + 1, m + 1, r); st[v] = merge(st[2 * v], st[2 * v + 1]); } } void upd(int x, int y, int v = 1, int l = 0, int r = n - 1) { if (l == r) { nums[x] = y; st[v] = node(nums[l], nums[l], 1); } else { int m = (l + r) / 2; if (x <= m) { upd(x, y, 2 * v, l, m); } else { upd(x, y, 2 * v + 1, m + 1, r); } st[v] = merge(st[2 * v], st[2 * v + 1]); } } } st; int segtree::n = 1; bool set_vals(int x, int y, ll cost, int first, int last) { auto &cur = min_dist[x][y]; bool ans = false; if (!cur.set[0]) { cur.min[0] = path(first, last, cost); cur.set[0] = true; ans = true; } if (!cur.set[1] && !same(cur.min[0].start, first)) { cur.min[1] = path(first, last, cost); cur.set[1] = true; ans = true; } if (!cur.set[2] && !same(cur.min[0].end, last)) { cur.min[2] = path(first, last, cost); cur.set[2] = true; ans = true; } if (!cur.set[3] && !same(cur.min[0].start, first) && !same(cur.min[0].end, last)) { cur.min[3] = path(first, last, cost); cur.set[2] = true; ans = true; } return ans; } void dijk(int x) { // {dist, pos, first edge, last edge} priority_queue<array<ll, 4>, vector<array<ll, 4>>, greater<array<ll, 4>>> pq; min_dist[x][x].set[0] = true; for (int e : adj[x]) { auto [nxt, cost] = edge[e]; pq.push({cost, nxt, e, e}); } while (!pq.empty()) { auto [cost, pos, first, last] = pq.top(); pq.pop(); bool res = set_vals(x, pos, cost, first, last); if (!res) continue; for (int e : adj[pos]) { if (!same(e, last)) { auto [nxt, cost2] = edge[e]; pq.push({cost + cost2, nxt, first, e}); } } } } int main() { cin.tie(0)->sync_with_stdio(0); cin >> n >> m >> t >> l; for (int i = 0; i < m; i++) { int a, b; ll c; cin >> a >> b >> c; a--; b--; adj[a].push_back(edge.size()); edge.push_back({b, c}); adj[b].push_back(edge.size()); edge.push_back({a, c}); } for (int i = 0; i < n; i++) { dijk(i); } for (int i = 0; i < l; i++) { cin >> nums[i]; nums[i]--; } segtree::n = l; st.build(); for (int i = 0; i < t; i++) { int p, q; cin >> p >> q; p--; q--; st.upd(p, q); if (st.st[1].combo.empty()) { cout << "-1\n"; } else { ll ans = INFLL; for (auto &p : st.st[1].combo) { ans = min(ans, p.length); } cout << ans << '\n'; } } return 0; }
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