Submission #16325

#	Time	Username	Problem	Language	Result	Execution time	Memory
16325		comet	Ideal city (IOI12_city)	C++98	100 / 100	107 ms	8596 KiB

city

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int,int> pp;
typedef vector<int> vec;
typedef vector<vec> mat;
#define pb push_back
#define MOD 1000000000

struct pt{
	int x,y,v;
	pt(){}
	pt(int x_,int y_):x(x_),y(y_){}
	bool operator<(const pt& r)const{
		return x!=r.x?x<r.x:y<r.y;
	}
}s[100000];

mat path;
int n;
int cnt[100000];

ll dfs(int v,int p,ll &ans){
	ll ret=0;
	for(int i=0;i<path[v].size();i++){
		int u=path[v][i];
		if(u==p)continue;
		ret+=dfs(u,v,ans);
	}
	ret+=cnt[v];
	ans+=(n-ret)*ret;
	ans%=MOD;
	return ret;
}

int f(int N, int *X, int *Y) {
	n=N;
	for(int i=0;i<N;i++)s[i]=pt(X[i],Y[i]);
	sort(s,s+N);
	int sz=0;
	for(int i=0;i<N;i++){
		int p=i;
		while(s[i].x==s[i+1].x)i++;
		int v=p;
		while(v<=i){
			while(v<i&&s[v].y+1==s[v+1].y){
				s[v].v=sz;
				v++;
			}
			s[v].v=sz;
			cnt[sz++]=s[v].y-s[p].y+1;
			p=++v;
		}
	}

	path.clear();
	path.assign(sz,vec());

	for(int i=0;i<N;i++){
	 	pt* it=lower_bound(s,s+N,pt(s[i].x-1,s[i].y));
		if(it->x==s[i].x-1&&it->y==s[i].y)path[s[i].v].pb(it->v);
		it=lower_bound(s,s+N,pt(s[i].x+1,s[i].y));
		if(it->x==s[i].x+1&&it->y==s[i].y)path[s[i].v].pb(it->v);
	}

	for(int i=0;i<sz;i++){
		sort(path[i].begin(),path[i].end());
		path[i].erase(unique(path[i].begin(),path[i].end()),path[i].end());
	}

	ll ret=0;
	dfs(0,0,ret);
	return (int)ret;
}

int DistanceSum(int N, int *X, int *Y){
	return (f(N,X,Y)+f(N,Y,X))%MOD;
}

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