You have r red, g green and b blue balloons. To decorate a single table for the banquet you need exactly three balloons. Three balloons attached to some table shouldn't have the same color. What maximum number t of tables can be decorated if we know number of balloons of each color?
Your task is to write a program that for given values r, g and b will find the maximum number t of tables, that can be decorated in the required manner.
The single line contains three integers r, g and b (0 ≤ r, g, b ≤ 2·109) — the number of red, green and blue baloons respectively. The numbers are separated by exactly one space.
Print a single integer t — the maximum number of tables that can be decorated in the required manner.
5 4 3
4
1 1 1
1
2 3 3
2
In the first sample you can decorate the tables with the following balloon sets: "rgg", "gbb", "brr", "rrg", where "r", "g" and "b" represent the red, green and blue balls, respectively.
题目大意:
一共三种颜色的气球,每种气球的个数已知,对应有一排桌子,我们需要对每一个桌子分配三个气球,但是一个桌子上的气球的颜色不能相同,问最多能够分配多少个桌子。
思路:
1、显然利用到贪心思想,每一次选取最多的颜色气球两个,加上最少的颜色的气球一个,分配到一个桌子上,但是因为数据很大,直接模拟一定会超时,那么考虑枚举找规律。
2、
①那么显然,如果最少数量的两个颜色的气球的数量总和乘以2如果小于等于另外颜色的气球的个数,显然答案是最少数量的两个颜色的气球个数和。
②其他情况经过枚举发现,因为我们在模拟过程中三种颜色的气球时大时小,其实一直模拟下去的解就是三种颜色的气球的总和/3.
Ac代码:
#include<stdio.h>
#include<string.h>
#include<algorithm>
using namespace std;
#define ll __int64
int main()
{
ll aa,bb,cc;
while(~scanf("%I64d%I64d%I64d",&aa,&bb,&cc))
{
ll a[5];
a[0]=aa;
a[1]=bb;
a[2]=cc;
sort(a出,a+3);
if(a[0]*2+a[1]*2<=a[2])
printf("%I64d",a[0]+a[1]);
else printf("%I64d\n",(a[0]+a[1]+a[2])/3);
}
}