Educational Codeforces Round 3 A – USB Flash Drives

链接: https://codeforces.com/contest/609/problem/A

public class TaskA {
    public void solve(int testNumber, InputReader in, OutputWriter out) {
        int n = in.readInt();
        int m = in.readInt();
        int res = 0;
        int[] ary = in.readIntArray(n);
        Arrays.sort(ary);
        for(int i = ary.length - 1; i>=0; i--) {
            if (m > 0 && ary[i] <= m){
                m -= ary[i];
                res++;
            }
            else if (m > 0 && ary[i] > m) {
                m -= ary[i];
                res++;
            }
        }
        out.print(res);
    }
}

先排序一下, 然后从大往小用贪婪思想选数, 注意选的时候的两个情况有先后, 第二种情况 出现是选最后一个数的时候.