Submission #922125

#	Time	Username	Problem	Language	Result	Execution time	Memory
922125		406	Road Closures (APIO21_roads)	C++17	100 / 100	424 ms	74200 KiB

roads

    #include "roads.h"
    #include <bits/stdc++.h>
    //PAIN ^ 2
    using namespace std;
    const int N = 1e5 + 5;
    const long long INF = 1ll << 60;
    long long dp[N][2];
    int X, p[N], deg[N];
    set<array<int, 2>> adj[N];
    vector<array<int, 2>> adjV[N];
    vector<int> rec;
    set<int> S;
    bitset<N> enb, mark;
     
    struct segment_tree {
    	vector<long long> sum, cnt;
    	int n = 0;
    	void init(int _n) {
    		n = _n;
    		sum.assign(4 * n, 0);
    		cnt.assign(4 * n, 0);
    	}
    	long long get(int x) {
    		if (x <= 0) return (x == 0 ? 0 : -INF);
    		int l = 0, r = n, v = 1;
    		long long s = 0;
    		while (r - l > 1) {
    			int m = l + r >> 1;
    			v <<= 1;
    			if (cnt[v] >= x) r = m;
    			else x -= cnt[v], s += sum[v], v |= 1, l = m;
    		}
    		return s + sum[v];
    	}
    	void add(int id, int x) {
    		int l = 0, r = n, v = 1;
    		while (r - l > 1) {
    			sum[v] += x, cnt[v]++;
    			int m = l + r >> 1;
    			v <<= 1;
    			if (id < m) r = m;
    			else l = m, v |= 1;
    		}
    		sum[v] += x, cnt[v]++;
    	}
    } SEG[N];
     
    void dfs(int v, int p) {
    	if (enb[v]) assert(0);
     
    	rec.push_back(v);
    	mark[v] = true;
     
    	long long dif = 0, ans = 0, mx = 0;
    	vector<long long> V;
    	V.reserve(adj[v].size());
     
    	for (auto P: adj[v]) {
    		int u = P[0], w = P[1];
    		if (u == p) continue;
    		dfs(u, v);
    		dif += dp[u][0];
    		V.push_back(w + dp[u][1] - dp[u][0]);
    	}
    	sort(V.rbegin(), V.rend());
    	dp[v][0] = dp[v][1] = 0;
    	for (int i = 0; i <= X && i <= V.size(); i++) {
    		if (i) ans += V[i - 1];
    		dp[v][0] = max(dp[v][0], SEG[v].get(X - i) + ans);
    		dp[v][1] = max(dp[v][1], SEG[v].get(X - i - 1) + ans);
    		//if (v == 0)
    			//cout << "i: " << i << " (chosen from V) that is " << ans << " SEG: " << SEG[v].get(X - i) << endl;
    	}
    	dp[v][0] += dif, dp[v][1] += dif;
    	//cout << "V: " << v << " SEG: " << SEG[v].kol << " dp[0] " << dp[v][0] << " dp[1] " << dp[v][1] << endl;
    }
     
    vector<long long> minimum_closure_costs(int n, vector<int> U, vector<int> V, vector<int> W) {
    	long long all = 0;
    	for (int i = 0; i < U.size(); i++) {
    		adj[U[i]].insert({V[i], W[i]});
    		adj[V[i]].insert({U[i], W[i]});
    		adjV[U[i]].push_back({-W[i], V[i]});
    		adjV[V[i]].push_back({-W[i], U[i]});
    		all += W[i];
    	}
    	for (int i = 0; i < n; i++) sort(adjV[i].begin(), adjV[i].end()), SEG[i].init(adjV[i].size());
     
    	iota(p, p + n, 0), sort(p, p + n, [&](const int x, const int y) {return adjV[x].size() < adjV[y].size();});
    	for (int i = 0; i < n; i++) S.insert(i);
     
    	vector<long long> re(n);
    	re[0] = all;
    	for (int i = 1, ptr = 0; i < n; i++) { //TODO
    		X = i; 
    		for (;ptr < n && adjV[p[ptr]].size() <= i; ptr++) {
    			int v = p[ptr];
    			array<int, 2> P;
    			for (auto P: adjV[v]) {
    				int u = P[1], w = -P[0];
    				if (enb[u]) all -= w;
    				else {
    					SEG[u].add(lower_bound(adjV[u].begin(), adjV[u].end(), array<int, 2>{-w, v}) - adjV[u].begin(), w);
    					//cout << "ADDING TO " << u << " edge: " << w << endl;
    				}
    				adj[v].erase(P);
    				adj[u].erase({v, w});
    			}
    			enb[v] = true;
    			S.erase(v);
    		}
    		long long ans = 0;
    		for (auto v: S) if (!mark[v]) {
    			//cout << "DFS: " << v << endl;
    			dfs(v, v);
    			ans += dp[v][0];
    		}
     
    		for (auto v: rec) mark[v] = 0;
    		rec.clear();
     
    		re[i] = all - ans;
    	}
    	return re;
    }

Compilation message (stderr)

roads.cpp: In member function 'long long int segment_tree::get(int)':
roads.cpp:28:18: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   28 |        int m = l + r >> 1;
      |                ~~^~~
roads.cpp: In member function 'void segment_tree::add(int, int)':
roads.cpp:39:18: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   39 |        int m = l + r >> 1;
      |                ~~^~~
roads.cpp: In function 'void dfs(int, int)':
roads.cpp:67:34: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   67 |      for (int i = 0; i <= X && i <= V.size(); i++) {
      |                                ~~^~~~~~~~~~~
roads.cpp:54:34: warning: unused variable 'mx' [-Wunused-variable]
   54 |      long long dif = 0, ans = 0, mx = 0;
      |                                  ^~
roads.cpp: In function 'std::vector<long long int> minimum_closure_costs(int, std::vector<int>, std::vector<int>, std::vector<int>)':
roads.cpp:80:24: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   80 |      for (int i = 0; i < U.size(); i++) {
      |                      ~~^~~~~~~~~~
roads.cpp:96:44: warning: comparison of integer expressions of different signedness: 'std::vector<std::array<int, 2> >::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   96 |       for (;ptr < n && adjV[p[ptr]].size() <= i; ptr++) {
      |                        ~~~~~~~~~~~~~~~~~~~~^~~~
roads.cpp:98:22: warning: unused variable 'P' [-Wunused-variable]
   98 |        array<int, 2> P;
      |                      ^

• Subtask 1: 5 / 5
• Subtask 2: 7 / 7
• Subtask 3: 14 / 14
• Subtask 4: 10 / 10
• Subtask 5: 17 / 17
• Subtask 6: 25 / 25
• Subtask 7: 22 / 22