HDU-6188(Duizi and Shunzi)

贪心, 优先找对子, 有一种特殊情况1 2 3 3 4 5这种情况优先顺子

#include <cstdio>
#include <cstring>
#include <iostream>
using namespace std;

const int MAXN = 1e6 + 5;
int arr[MAXN];

int main() {
  int n, res;
  while (cin >> n) {
    res = 0;
    memset(arr, 0, sizeof(arr));
    for (int i = 0; i < n; ++i) {
      int t;
      cin >> t;
      arr[t]++;
    }
    for (int i = 1; i <= MAXN - 1; ++i) {
      if (arr[i - 1] == 1 && arr[i - 2] == 1 && arr[i] > 0) {
        arr[i]--;
        arr[i - 1]--;
        arr[i - 2]--;
        res++;
      }
      res += arr[i] / 2;
      arr[i] %= 2;
    }
    cout << res << endl;
  }
}