Submission #100429

#	Time	Username	Problem	Language	Result	Execution time	Memory
100429		JPN20	Construction of Highway (JOI18_construction)	C++17	16 / 100	2041 ms	20464 KiB

construction

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

class RangeMax {
	public:
	vector<int>dat; int size_ = 1;
	
	void init(int sz) {
		while (size_ <= sz) size_ *= 2;
		dat.resize(size_ * 2, 0);
	}
	void update(int pos, int x) {
		pos += size_;
		dat[pos] = x;
		
		while (pos >= 2) {
			pos >>= 1;
			dat[pos] = max(dat[pos * 2], dat[pos * 2 + 1]);
		}
	}
	int query_(int l, int r, int a, int b, int u) {
		if (l <= a && b <= r) return dat[u];
		if (b <= l || r <= a) return -(1 << 30);
		
		int s1 = query_(l, r, a, (a + b) >> 1, u * 2);
		int s2 = query_(l, r, (a + b) >> 1, b, u * 2 + 1);
		return max(s1, s2);
	}
	int query(int l, int r) {
		return query_(l, r, 0, size_, 1);
	}
};

class BIT {
	public:
	vector<int>bit; int size_;
	
	void init(int sz) {
		size_ = sz + 2;
		bit.resize(size_ + 1, 0);
	}
	void add(int pos, int x) {
		pos++;
		while (pos <= size_) {
			bit[pos] += x; pos += (pos & -pos);
		}
	}
	int sum(int pos) {
		int s = 0; pos++;
		while (pos >= 1) {
			s += bit[pos]; pos -= (pos & -pos);
		}
		return s;
	}
};

long long check_inversions(vector<pair<int, int>> vec) {
	vector<int> A;
	for (int i = 0; i < (int)vec.size(); i++) A.push_back(vec[i].first);
	
	sort(A.begin(), A.end());
	A.erase(unique(A.begin(), A.end()), A.end());
	for (int i = 0; i < (int)vec.size(); i++) vec[i].first = lower_bound(A.begin(), A.end(), vec[i].first) - A.begin();
	
	BIT Z; Z.init(A.size() + 1);
	
	long long ans = 0;
	for (int i = 0; i < (int)vec.size(); i++) {
		ans += 1LL * vec[i].second * (Z.sum(A.size()) - Z.sum(vec[i].first));
		Z.add(vec[i].first, vec[i].second);
	}
	return ans;
}

int N, C[1 << 17], A[1 << 17], B[1 << 17], dist[1 << 17], dp[1 << 17][20];
int cl[1 << 17], cr[1 << 17], cnts;
vector<int> X[1 << 17];
RangeMax Q;

void dfs(int pos, int dep) {
	cnts++; cl[pos] = cnts; dist[pos] = dep;
	for (int i = 0; i < (int)X[pos].size(); i++) {
		if (dist[X[pos][i]] != -1) continue;
		dp[X[pos][i]][0] = pos;
		dfs(X[pos][i], dep + 1);
	}
	cr[pos] = cnts;
}

int prevs(int pos, int x) {
	for (int i = 19; i >= 0; i--) {
		if (x >= (1 << i)) { x -= (1 << i); pos = dp[pos][i]; }
	}
	if (pos == 0) pos = 1;
	return pos;
}

vector<pair<int, int>> get_inverse(int pos) {
	vector<pair<int, int>> U;
	while (true) {
		// Binary Search.
		int L = 0, R = dist[pos] + 1, M, maxn = (1 << 30);
		int E = Q.query(cl[pos], cr[pos] + 1);
		
		for (int i = 0; i < 20; i++) {
			M = (L + R) / 2;
			int G = prevs(pos, M);
			int P = Q.query(cl[G], cr[G] + 1); //cout << "query(" << G << ") = " << P << endl;
			if (E != P) { maxn = min(maxn, M); R = M; }
			else { L = M; }
		}
		
		if (maxn == (1 << 30)) { U.push_back(make_pair(C[B[E]], dist[pos] + 1)); break; }
		U.push_back(make_pair(C[B[E]], maxn));
		pos = prevs(pos, maxn);
	}
	reverse(U.begin(), U.end());
	return U;
}

int main() {
	scanf("%d", &N);
	for (int i = 1; i <= N; i++) scanf("%d", &C[i]);
	for (int i = 1; i <= N - 1; i++) {
		scanf("%d%d", &A[i], &B[i]);
		X[A[i]].push_back(B[i]);
		X[B[i]].push_back(A[i]);
	}
	
	for (int i = 1; i <= N; i++) dist[i] = -1;
	dfs(1, 0);
	
	for (int i = 0; i < 19; i++) {
		for (int j = 1; j <= N; j++) dp[j][i + 1] = dp[dp[j][i]][i];
	}
	
	//for (int i = 1; i <= N; i++) cout << i << ": cl = " << cl[i] << ", cr = " << cr[i] << endl;
	
	Q.init(N + 2); Q.update(cl[1], 0);
	for (int i = 1; i <= N - 1; i++) {
		vector<pair<int, int>> T = get_inverse(A[i]);
		//cout << "For query " << i << ":" << endl;
		//for (int j = 0; j < T.size(); j++) cout << "(" << T[j].first << ", " << T[j].second << ") ";
		//cout << endl;
		
		printf("%lld\n", check_inversions(T));
		Q.update(cl[B[i]], i);
	}
	return 0;
}

Compilation message (stderr)

construction.cpp: In function 'int main()':
construction.cpp:122:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &N);
  ~~~~~^~~~~~~~~~
construction.cpp:123:36: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  for (int i = 1; i <= N; i++) scanf("%d", &C[i]);
                               ~~~~~^~~~~~~~~~~~~
construction.cpp:125:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d", &A[i], &B[i]);
   ~~~~~^~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 7 / 7
• Subtask 2: 9 / 9
• Subtask 3: 0 / 84