Educational Codeforces Round 21

B. Average Sleep Time

题目地址：http://codeforces.com/contest/808/problem/B

思路：简单数组压缩，注意要用long

AC代码：

import java.text.DecimalFormat;
import java.util.Scanner;


public class Main {

	static long[] num = new long[200010];
	
	public static void main(String[] args) {
		
		Scanner in = new Scanner(System.in);
		while (in.hasNextInt()) {
			int n = in.nextInt();
			int k = in.nextInt();
			num[0] = 0;
			long x;
			for (int i=1; i<=n; i++) {
				x = in.nextLong();
				num[i] = num[i-1] + x;
			}
			long sum = 0;
			for (int i=1; i<=n-k+1; i++) {
				sum += num[i+k-1] - num[i-1];
			}
			DecimalFormat df = new DecimalFormat("0.0000000000");
			double y = sum * 1.0 / (n - k + 1);
			System.out.println(df.format(y));
		}
	}

}

C. Tea Party

题目地址：http://codeforces.com/contest/808/problem/C

思路：先把每个人的一般倒满，把剩下的依次在最大的瓶子中倒，倒满一个倒下一个，直到倒完，有一个注意点是，如果瓶子i的体积比瓶子j的体积大时，i瓶子放的茶大于等于j瓶子放的茶，如茶总共有8升，杯子为8升 7升，2个杯子的体积都是4升

AC代码；

#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <algorithm>
using namespace std;
struct cup
{
    int total;
    int save;
    int index;
}cups[110];
bool cmp(cup a,cup b)
{
    return a.total > b.total;
}
bool cmp2(cup a,cup b)
{
    return a.index < b.index;
}
int main()
{
    int n,w;
    while (scanf("%d%d",&n,&w) != EOF)
    {
        int total = 0;
        int temp = 0;
        for (int i=0; i<n; i++)
        {
            scanf("%d",&cups[i].total);
            temp = (cups[i].total + 1) >> 1;
            total += temp;
            cups[i].save = temp;
            cups[i].index = i;
        }
        if (total > w)
        {
            printf("-1\n");
        }
        else
        {
            sort(cups,cups+n,cmp);
            w -= total;
            for (int i=0; i<n; i++)
            {
                if (w >= cups[i].total - cups[i].save)
                {
                    //这一句一定要放前面
                    w -= (cups[i].total - cups[i].save);
                    cups[i].save = cups[i].total;
                }
                else if (w < cups[i].total - cups[i].save)
                {
                    cups[i].save += w;
                    w = 0;
                }
                if (!w)
                {
                    break;
                }
            }
            sort(cups,cups+n,cmp2);
            for (int i=0; i<n; i++)
            {
                printf("%d ",cups[i].save);
            }
            printf("\n");
        }
    }
    return 0;
}