Submission #528068

#	Time	Username	Problem	Language	Result	Execution time	Memory
528068		CSQ31	Coin Collecting (JOI19_ho_t4)	C++17	0 / 100	1 ms	204 KiB

joi2019_ho_t4

#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;
ll dp[200005][3];
int main()
{
	int n;
	cin>>n;
	ll ans = 0;
	vector<array<int,2>>a(2*n);
	for(int i=0;i<2*n;i++){
		int x,y;
		cin>>x>>y;
		a[i][0] = x;
		if(y>=2)ans+=y-2;
		else ans+=1-y;
		a[i][1] = y>=2;
	}
	sort(a.begin(),a.end());
	int m = 2*n;
	for(int i=0;i<m;i++)ans+=abs(a[i][0] - (i/2 + 1));
	//cout<<ans<<'\n';
	
	//obs that matching in increasing order of x is optimal
	//problem reduced to how to optimize for y 
	//0 match with 1  = + 1 cost
	vector<int>c0,c1;
	for(int i=0;i<m;i++){
		int j = i;
		while(j+1<m && a[j+1][0] == a[i][0])j++;
		vector<int>b(2,0);
		for(int k=i;k<=j;k++)b[a[k][1]]++;
		c0.push_back(b[0]);
		c1.push_back(b[1]);
		i=j;
	}
	/*
	for(int x:c0)cout<<x<<" ";
	cout<<'\n';
	for(int x:c1)cout<<x<<" ";
	cout<<'\n';
	*/
	n = c0.size();
	for(int i=0;i<=n;i++)dp[i][0] = dp[i][1] = 1e18;
	dp[0][0] = 0;
	int cur = 0;
	for(int i=0;i<n;i++){
		//cout<<i<<" "<<dp[i][0]<<" "<<dp[i][1]<<'\n';
		vector<int>b(2,0);
		int ncur = cur+c0[i]+c1[i];
		for(int j=cur;j<ncur;j++)b[j%2]++;
		if(c0[i]+c1[i] == 1){ //corner case
			ll cc0 = cur%2?dp[i][1] : dp[i][0];
			ll cc1 = cur%2?dp[i][0] : dp[i][1];
			dp[i+1][0] = min(dp[i+1][0], min(1-c0[i]+cc0,1-c1[i]+cc1));
			if(ncur%2){//swap in a zero
				//x0
				//x = 0 does nothing
				dp[i+1][1] = min(dp[i+1][1],1-c0[i] + cc1);
			}
		}else{
			dp[i+1][0] = min(dp[i+1][0],dp[i][0] + max(c0[i] - b[0],c1[i] - b[1]));
			b[0]++;b[1]--;
			dp[i+1][0] = min(dp[i+1][0],dp[i][1] + max(c0[i] - b[0],c1[i] - b[1]));
			b[0]--;b[1]++;
			
			if(ncur%2){
				b[0]--;
				b[1]++;
				dp[i+1][1] = min(dp[i+1][1],dp[i][0] + max(c0[i] - b[0],c1[i] - b[1]));
				b[0]++;b[1]--;
				dp[i+1][1] = min(dp[i+1][1],dp[i][1] + max(c0[i] - b[0],c1[i] - b[1]));
				b[0]--;b[1]++; 
			} 
		}
		cur = ncur;
	}
	cout<<ans + min(dp[n][0],dp[n][1]);
}

• Subtask 1: 0 / 8
• Subtask 2: 0 / 29
• Subtask 3: 0 / 63