Submission #551480

#	Time	Username	Problem	Language	Result	Execution time	Memory
551480		1ne	Fountain Parks (IOI21_parks)	C++17	15 / 100	3600 ms	131576 KiB

parks

#include "parks.h"
#include<bits/stdc++.h>
using namespace std;
struct edges{
	int x,y,x1,y1;
};
int construct_roads(std::vector<int> x, std::vector<int> y) {
	 map<pair<int,int>,bool>mp,got;
	 map<pair<int,int>,int>index,need;
	 int n = (int)x.size();
	 for (int i = 0;i<n;++i){
		 mp[{x[i],y[i]}] = true;
		 got[{x[i],y[i]}] = false;
		 index[{x[i],y[i]}] = i;
	 }
	 auto comp = [&](int a,int b,int c,int d){
		if (a<c){
			return (edges){a,b,c,d};
		}
		else if (c < a){
				return (edges){c,d,a,b};
		}
		else if ( b < d){
			return (edges){a,b,c,d};
		}
		return (edges){c,d,a,b};
	 };
	 vector<edges>ans;
	 vector<int>dx = {2,0,-2,0};
	 vector<int>dy = {0,2,0,-2};
	 function<void(int,int)> dfs = [&](int u,int v){
		 got[{u,v}] = true;
		 for (int i = 0;i<4;++i){
			 int xx = u + dx[i];
			 int yy = v + dy[i];
			 if (mp[{xx,yy}] && !got[{xx,yy}]){
				 ans.push_back(comp(u,v,xx,yy));
				 dfs(xx,yy);
			 }
		 }
	 };
	 bool ok = true;
	 dfs(x[0],y[0]);
	 for (int i = 0;i<n;++i){
		 if (!got[{x[i],y[i]}]){
			 ok=false;
			 break;
		 }
	 }
	 if (!ok){
		 return 0;
	 }
	 sort(ans.begin(),ans.end(),[&](auto xx,auto yy){
		 if (xx.x == yy.x)return xx.y < yy.y; 
		 return xx.x<yy.x;
	 });
	 vector<int>u,v,a,b;
	 priority_queue<pair<int,int>,vector<pair<int,int>>,greater<pair<int,int>>>q;
	 for (int i = 0;i<(int)ans.size();++i){
		swap(ans[i].x,ans[i].x1);
		swap(ans[i].y,ans[i].y1);
		edges z = ans[i];
		if (z.x == z.x1){
			need[{z.x - 1,z.y - 1}]++;
			need[{z.x + 1,z.y - 1}]++;
		}
		else{
			need[{z.x - 1,z.y + 1}]++;
			need[{z.x - 1,z.y - 1}]++;
		}
	 }
	 for (int i = 0;i<(int)ans.size();++i){
		 edges z = ans[i];
		 int cost = 0;
		 if (z.x == z.x1){
			 cost = min(need[{z.x - 1,z.y - 1}],need[{z.x + 1,z.y - 1}]);
		}
		else{
			 cost = min(need[{z.x - 1,z.y - 1}],need[{z.x - 1,z.y + 1}]);
		}
		q.push({cost,i});
	 }
	 while(!q.empty()){
		auto z = ans[q.top().second];
		int temp = q.top().second;
		q.pop();
		if (z.x == z.x1){
			if (need[{z.x - 1,z.y - 1}]==1){
				need[{z.x - 1,z.y - 1}] = INT_MAX;
				need[{z.x + 1,z.y - 1}]--;
				u.push_back(index[{z.x,z.y}]);
				v.push_back(index[{z.x1,z.y1}]);
				a.push_back(z.x - 1);
				b.push_back(z.y - 1);
			}
			else if (need[{z.x + 1,z.y - 1}]==1){
				need[{z.x - 1,z.y  - 1}]--;
				need[{z.x + 1,z.y - 1}] = INT_MAX;
				u.push_back(index[{z.x,z.y}]);
				v.push_back(index[{z.x1,z.y1}]);
				a.push_back(z.x + 1);
				b.push_back(z.y - 1);
			}
			else q.push({min(need[{z.x - 1,z.y - 1}],need[{z.x + 1,z.y - 1}]),temp});
		}
		else{
			if (need[{z.x - 1,z.y + 1}]==1){
				need[{z.x - 1,z.y + 1}] = INT_MAX;
				need[{z.x - 1,z.y-1}]--;
				u.push_back(index[{z.x,z.y}]);
				v.push_back(index[{z.x1,z.y1}]);
				a.push_back(z.x - 1);
				b.push_back(z.y + 1);
			}
			else if (need[{z.x - 1,z.y - 1}]==1){
				need[{z.x - 1,z.y + 1}]--;
				need[{z.x - 1,z.y - 1}] = INT_MAX;
				u.push_back(index[{z.x,z.y}]);
				v.push_back(index[{z.x1,z.y1}]);
				a.push_back(z.x - 1);
				b.push_back(z.y - 1);
			}
			else q.push({min(need[{z.x - 1,z.y + 1}],need[{z.x - 1,z.y - 1}]),temp});
		}
	 }
	 
	
	 build(u,v,a,b);
    return 1;
}

• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 0 / 15
• Subtask 4: 0 / 20
• Subtask 5: 0 / 20
• Subtask 6: 0 / 30