Submission #56839

#	Time	Username	Problem	Language	Result	Execution time	Memory
56839		Mamnoon_Siam	Election Campaign (JOI15_election_campaign)	C++17	20 / 100	1083 ms	58636 KiB

election_campaign

//#pragma GCC optimize("Ofast,unroll-loops,no-stack-protector")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")

#include <bits/stdc++.h>
using namespace std;

#define debug(s) cout<< #s <<" = "<< s <<endl
#define all(v) (v).begin(), (v).end()
#define KeepUnique(v) (v).erase( unique(all(v)), v.end() )
#define MEMSET(a,val) memset(a, val, sizeof a)
#define PB push_back
#define endl '\n'
typedef long long ll;

inline int myrand(int l, int r) {
	int ret = rand(); ret <<= 15; ret ^= rand();
	if(ret < 0) ret = -ret; ret %= (r-l+1); ret += l;
	return ret;
}
template <typename F, typename S>
ostream& operator << (ostream& os, const pair< F, S>& p) {
    return os<<"(" <<p.first<<", "<<p.second<<")"; }

typedef pair<int, int> ii;
template<typename T> using min_pq =
	priority_queue<T, vector<T>, greater<T> >;

//int dx[] = {-1, +0, +1, +0};
//int dy[] = {+0, +1, +0, -1};

const int maxn = 100005;

int n, m;
vector<int> g[maxn];
int lvl[maxn];
vector<int> paths[maxn];
vector<int> A, B, C;
vector<int> shitz[maxn], pathnodes[maxn];
int t[18][maxn];
int dp[maxn];
int S[maxn];

int dfs(int u, int par) {
	t[0][u] = par;
	lvl[u] = par == -1 ? 0 : lvl[par] + 1;
	for(int v : g[u]) {
		if(par - v) {
			dfs(v, u);
		}
	}
}

int __lca(int u, int v) {
	if(lvl[u] > lvl[v]) swap(u, v);
	int d = lvl[v] - lvl[u];
	for(int i = 16; i >= 0; i--) {
		if(d & (1 << i)) {
			v = t[i][v];
		}
	}
	if(u == v) return u;
	for(int i = 16; i >= 0; i--) {
		if(t[i][u] != t[i][v]) {
			u = t[i][u];
			v = t[i][v];
		}
	} return t[0][u];
}

int pathcost(int i, int ret = 0) {
	for(int u : pathnodes[i]) ret += S[u]; return ret;
}

void prep(int u, int par) {
	for(int v : g[u]) {
		if(v - par) {
			prep(v, u);
			S[u] += dp[v];
		}
	}
	dp[u] = S[u];
	for(int p : paths[u]) {
		int ret = C[p] + pathcost(p);
		dp[u] = max(dp[u], ret);
	}
	S[u] -= dp[u];
}

int32_t main () {
	// freopen("in", "r", stdin);
	cin >> n;
	for(int i = 1; i < n; i++) {
		int u, v; cin >> u >> v;
		g[u].push_back(v);
		g[v].push_back(u);
	}
	MEMSET(t, -1);
	dfs(1, -1);
	for(int p = 1; p <= 16; p++) {
		for(int i = 1; i <= n; i++) {
			int mid = t[p - 1][i];
			if(mid != -1) t[p][i] = t[p - 1][mid];
		}
	}
	cin >> m;
	A.resize(m), B.resize(m), C.resize(m);
	for(int i = 0; i < m; i++) {
		cin >> A[i] >> B[i] >> C[i];
		int lca = __lca(A[i], B[i]);
		paths[lca].push_back(i);
	}
	for(int i = 0; i < m; i++) {
		set<int> st;
		int lca = __lca(A[i], B[i]), now;

		now = A[i];
		while(now != lca) st.insert(now), now = t[0][now];
		now = B[i];
		while(now != lca) st.insert(now), now = t[0][now];
		st.insert(lca);
		
		for(int b : st) pathnodes[i].push_back(b);
		// set<int> All;
		// for(int u : st) {
		// 	for(int v : g[u]) {
		// 		All.insert(v);
		// 	}
		// }
		// for(int u : st) All.erase(u); // remove all nodes on path
		// if(t[0][lca] != -1) All.erase(t[0][lca]); // remove parent of lca
		// for(int u : All) {
		// 	shitz[i].push_back(u);
		// }
	}
	prep(1, -1);
	cout << dp[1] << endl;
}

Compilation message (stderr)

election_campaign.cpp: In function 'int myrand(int, int)':
election_campaign.cpp:17:2: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
  if(ret < 0) ret = -ret; ret %= (r-l+1); ret += l;
  ^~
election_campaign.cpp:17:26: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
  if(ret < 0) ret = -ret; ret %= (r-l+1); ret += l;
                          ^~~
election_campaign.cpp: In function 'int dfs(int, int)':
election_campaign.cpp:51:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^
election_campaign.cpp: In function 'int pathcost(int, int)':
election_campaign.cpp:71:2: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
  for(int u : pathnodes[i]) ret += S[u]; return ret;
  ^~~
election_campaign.cpp:71:41: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
  for(int u : pathnodes[i]) ret += S[u]; return ret;
                                         ^~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 0 / 5
• Subtask 3: 0 / 5
• Subtask 4: 0 / 30
• Subtask 5: 10 / 10
• Subtask 6: 0 / 40