LOJ #2455. 「POI2010」最小化遊戲 The Minima Game

#include <bits/stdc++.h>

using namespace std;
int a[1000010], n, ans;

int main(int argc, char const *argv[]) {
  cin >> n;
  for (int i = 1; i <= n; i++) scanf("%d", &a[i]);
  sort(a + 1, a + n + 1);
  for (int i = 1; i <= n; i++) ans = max(ans, a[i] - ans);
  return cout << ans << endl, 0;
}