Submission #395123

#	Time	Username	Problem	Language	Result	Execution time	Memory
395123		johutha	Wiring (IOI17_wiring)	C++17	100 / 100	40 ms	7840 KiB

wiring

#include "wiring.h"
#include <iostream>
#include <algorithm>

#define int long long

using namespace std;

int min_total_length(vector<signed> rs, vector<signed> bs)
{
	vector<signed> xs;
	vector<bool> cols;

	int pr = 0;
	int pb = 0;

	while (pr < (int)rs.size() || pb < (int)bs.size())
	{
		if (pr >= (int)rs.size() || (pb < (int)bs.size() && bs[pb] < rs[pr]))
		{
			xs.push_back(bs[pb]);
			cols.push_back(false);
			pb++;
		}
		else
		{
			xs.push_back(rs[pr]);
			cols.push_back(true);
			pr++;
		}
	}

	int n = xs.size();

	vector<int> ds(n, 1e15);
	vector<int> locc = {(int)-1e15, (int)-1e15};

	for (int i = 0; i < n; i++)
	{
		ds[i] = min(ds[i], xs[i] - locc[!cols[i]]);
		locc[cols[i]] = xs[i];
	}

	locc = {(int)1e15, (int)1e15};
	for (int i = n - 1; i >= 0; i--)
	{
		ds[i] = min(ds[i], locc[!cols[i]] - xs[i]);
		locc[cols[i]] = xs[i];
	}

	vector<int> dp(n + 1, 1e15);
	dp[0] = 0;

	auto proc_change = [&](int r)
	{
		int c = 0;
		for (int d = 0; r + d < n && r - 1 - d >= 0 && cols[r + d] == cols[r] && cols[r - 1 - d] == cols[r - 1]; d++)
		{
			c += xs[r + d] - xs[r - 1 - d];
			dp[r + d + 1] = min(dp[r + d + 1], dp[r - 1 - d] + c);
		}
	};

	for (int i = 1; i <= n; i++)
	{
		if (i > 1 && cols[i - 1] != cols[i - 2]) proc_change(i - 1);
		dp[i] = min(dp[i], dp[i - 1] + ds[i - 1]);
	}
	
	return dp.back();
}

• Subtask 1: 7 / 7
• Subtask 2: 13 / 13
• Subtask 3: 10 / 10
• Subtask 4: 25 / 25
• Subtask 5: 45 / 45