Official Analysis (C++)

Explanation

We can consider three possibilities:

• Farmer John did not use any teleporter to transport the manure, so he travels a distance of $|a - b|$.
• Farmer John travels to point $x$ from $a$, teleports the manure to $y$, then travels to $b$, for a distance of $|a - x| + |b - y|$.
• Farmer John travels to point $y$ from $a$, teleports the manure to $x$, then travels to $b$, for a distance of $|a - y| + |b - x|$.

We can calculate the minimum distance he needs to haul the manure using his tractor among the above possibilities.

Implementation

Time Complexity: $\mathcal{O}(1)$

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#include <bits/stdc++.h>
using namespace std;

int main() {
	freopen("teleport.in", "r", stdin);
	freopen("teleport.out", "w", stdout);

	int a, b, c, d;
	cin >> a >> b >> c >> d;
	/*