Submission #32163

#	Time	Username	Problem	Language	Result	Execution time	Memory
32163		imeimi2000	Ideal city (IOI12_city)	C++14	100 / 100	73 ms	8268 KiB

city

#include <algorithm>
#include <vector>

using namespace std;
typedef long long llong;
typedef pair<int, int> pi;

int n;
const int MOD = 1e9;
const int PMAX = 2147483646;
pi point[100000];
int idx[100000];
int cnt[100000];
vector<int> edge[100000];

bool haveNext(int i) {
	if (i == n - 1) return false;
	if (point[i].first != point[i + 1].first) return false;
	if (point[i].second + 1 != point[i + 1].second) return false;
	return true;
}

int bsearch(pi x) {
	int s = 0, e = n - 1;
	int m;
	while (s < e) {
		m = (s + e) / 2;
		if (point[m] == x) return m;
		if (point[m] < x) s = m + 1;
		else e = m - 1;
	}
	if (point[s] == x) return s;
	return -1;
}

int ans;
int dfs(int x, int p) {
	int ret = cnt[x];
	for (int i : edge[x]) {
		if (i == p) continue;
		ret += dfs(i, x);
	}
	if (x) {
		llong sum = ret;
		sum *= n - ret;
		ans = (ans + sum) % MOD;
	}
	return ret;
}

int getAns() {
	ans = 0;
	sort(point, point + n);
	idx[0] = 0;
	edge[0].clear();
	cnt[0] = 1;
	for (int i = 1; i < n; ++i) {
		if (haveNext(i - 1)) ++cnt[idx[i] = idx[i - 1]];
		else cnt[idx[i] = idx[i - 1] + 1] = 1, edge[idx[i]].clear();
		int j = bsearch({ point[i].first - 1, point[i].second });
		if (j == -1) continue;
		if (!edge[idx[i]].empty() && idx[j] == edge[idx[i]].back()) continue;
		edge[idx[i]].push_back(idx[j]);
		edge[idx[j]].push_back(idx[i]);
	}
	dfs(0, -1);
	return ans;
}

int DistanceSum(int N, int *X, int *Y) {
	n = N;
	for (int i = 0; i < n; ++i) {
		point[i] = { X[i], Y[i] };
	}
	int t = getAns();
	for (int i = 0; i < n; ++i) {
		point[i] = { Y[i], X[i] };
	}
	return (getAns() + t) % MOD;
}

• Subtask 1: 11 / 11
• Subtask 2: 21 / 21
• Subtask 3: 23 / 23
• Subtask 4: 45 / 45