贪心 Codeforces Round #304 (Div. 2) B. Soldier and Badges

 

题目传送门

/*
    题意：问最少增加多少值使变成递增序列
    贪心：排序后，每一个值改为前一个值+1，有可能a[i-1] = a[i] + 1，所以要 >=
*/
#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;

typedef long long ll;

const int MAXN = 3e3 + 10;
const int INF = 0x3f3f3f3f;
int a[MAXN];

int main(void)        //Codeforces Round #304 (Div. 2) B. Soldier and Badges
{
    int n;
    while (scanf ("%d", &n) == 1)
    {
        for (int i=1; i<=n; ++i)    scanf ("%d", &a[i]);
        sort (a+1, a+1+n);

        int tot = 0;    a[0] = 0;
        for (int i=1; i<=n; ++i)
        {
            if (a[i-1] >= a[i])    {tot += (a[i-1] - a[i] + 1); a[i] = a[i-1] + 1;}
        }

        printf ("%d\n", tot);
    }

    return 0;
}

/*
4
1 3 1 4
5
1 2 3 2 5
4
4 3 2 2
*/