제출 #577240

#제출 시각아이디문제언어결과실행 시간메모리
577240Justin1이상적인 도시 (IOI12_city)C++14
55 / 100
614 ms40844 KiB
#include <bits/stdc++.h>
#define f first
#define s second
#define ll long long
#define pii pair<int,int>
using namespace std;
 
vector<pii> dir = {{0,1},{1,0},{-1,0},{0,-1}};
unordered_map<int,int> ar[100005], v[100005];
ll ans = 0, n;
ll cntX[100005], cntY[100005];
 
void dfs(int x, int y, ll sum) {
	ans += sum;
	v[x][y] = 1;
	if (!v[x-1][y] && ar[x-1][y]) dfs(x-1,y,sum+cntX[n]-2*cntX[x-1]);
	if (!v[x+1][y] && ar[x+1][y]) dfs(x+1,y,sum-cntX[n]+2*cntX[x]);
	if (!v[x][y-1] && ar[x][y-1]) dfs(x,y-1,sum+cntY[n]-2*cntY[y-1]);
	if (!v[x][y+1] && ar[x][y+1]) dfs(x,y+1,sum-cntY[n]+2*cntY[y]);
}
 
ll bfs(int sx, int sy) {
	ll ans = 0;
	queue<pair<pii,int>> nxt;
	nxt.push({{sx,sy},0});
	while (!nxt.empty()) {
		auto tmp = nxt.front();
		nxt.pop();
		if (v[tmp.f.f][tmp.f.s]) continue;
		v[tmp.f.f][tmp.f.s] = 1;
		ans += tmp.s;
		for (auto i : dir) {
			if (!v[tmp.f.f+i.f][tmp.f.s+i.s] && ar[tmp.f.f+i.f][ tmp.f.s+i.s]) {
				nxt.push({{tmp.f.f+i.f, tmp.f.s+i.s}, tmp.s+1});
			}
		}
	}  
	return ans;
}

int DistanceSum(int N, int *X, int *Y) {
	if (N <= 2000) {
		int mnX = INT_MAX, mnY = INT_MAX;
		for (int i = 0; i < N; i++) mnX = min(mnX, X[i]);
		for (int i = 0; i < N; i++) mnY = min(mnY, Y[i]);
		for (int i = 0; i < N; i++) X[i] -= mnX-1;
		for (int i = 0; i < N; i++) Y[i] -= mnY-1;
		ll ans = 0;
		for (int i = 0; i < N; i++) ar[X[i]][Y[i]] = 1;
		for (int i = 0; i < N; i++) {
			for (int j = 0; j < N; j++) v[X[j]][Y[j]] = 0;
			ans += bfs(X[i],Y[i]);
		}
		return (ans/2) % 1'000'000'000;
	} else {
		n = N;
		int mnX = INT_MAX, mnY = INT_MAX;
		for (int i = 0; i < N; i++) mnX = min(mnX, X[i]);
		for (int i = 0; i < N; i++) mnY = min(mnY, Y[i]);
		for (int i = 0; i < N; i++) X[i] -= mnX-1;
		for (int i = 0; i < N; i++) Y[i] -= mnY-1;
	
		for (int i = 0; i < N; i++) cntX[X[i]]++, cntY[Y[i]]++;
		for (int i = 1; i <= N; i++) cntX[i] += cntX[i-1], cntY[i] += cntY[i-1];
		for (int i = 0; i < N; i++) ar[X[i]][Y[i]] = 1;
		int tmp = 0;
		for (int i = 1; i < N; i++) tmp += abs(X[i]-X[0]) + abs(Y[i]-Y[0]);
		dfs(X[0], Y[0], tmp);
		return (ans/2) % 1'000'000'000;
	}
}
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