546B Soldier and Badges

模拟：

依题意模拟即可。

别忘了把数组开大来！

#include <iostream>
using namespace std;
const int N = 100010;
int n;
int a[N];
int main () {
	cin >> n;
	for (int i = 1;i <= n;i++) {
		int x;
		cin >> x;
		a[x]++;
	}
	int sum = 0,cnt = 0,i = 1;
	while (sum != n) {
		while (a[i] > 1) {
			a[i]--,a[i+1]++;
			cnt++;
		}
		sum += a[i++];
	}
	cout << cnt << endl;
	return 0;
}