首页 > ACM题库 > HDU-杭电 > HDU 3420-Bus Fair-贪心-[解题报告]HOJ
2014
03-23

HDU 3420-Bus Fair-贪心-[解题报告]HOJ

Bus Fair

问题描述 :

You are now in Foolish Land. Once moving in Foolish Land you found that there is a strange Bus fair system. The fair of moving one kilometer by bus in that country is one coin. If you want to go to X km and your friend wants to go to Y km then you can buy a ticket of X+Y coins (you are also allowed to buy two or more tickets for you two).
  
Now as a programmer, you want to show your creativity in buying tickets! Suppose, your friend wants to go 1 km and you want to go 2 km. Then it’s enough for you to buy a 2coin ticket! Because both of you are valid passengers before crossing the first km. and when your bus cross the first km your friend gets down from the bus. So you have the ticket of 2km! And you can safely reach to your destination, 2km using that ticket.
  
Now, you have a large group of friends and they want to reach to different distance. You think that you are smart enough that you can buy tickets that should manage all to reach their destination spending the minimum amount of coins. Then tell us how much we should at least pay to reach our destination.

输入:

There are multiple test cases. Each case start with a integer n, the total number of people in that group. 0<=n<=1000. Then comes n integers, each of them stands for a distance one of the men of the group wants to go to. You can assume that the distance a man wants to go is always less than 10000.

输出:

There are multiple test cases. Each case start with a integer n, the total number of people in that group. 0<=n<=1000. Then comes n integers, each of them stands for a distance one of the men of the group wants to go to. You can assume that the distance a man wants to go is always less than 10000.

样例输入:

2
1
2
2
2
3

样例输出:

2
4

#include<stdio.h>
#include<stdlib.h>
int cmp(const void *a, const void *b){
    return *(int *)a - *(int *)b;
}
int main() {
    int x[1001], n, i, j, tickets;
    while(scanf("%d", &n) != EOF){
        for(i = 0; i < n; i++) 
            scanf("%d", x + i);
        qsort(x, n, sizeof(x[0]), cmp);
        tickets = 0;
        for(i = 0; i < n; i++)
            if(x[i] * (n - i) > tickets) 
                tickets = x[i] * (n - i);
        printf("%d\n", tickets);
    }
}

参考:http://blog.csdn.net/dongdongzhang_/article/details/7956048


  1. 题本身没错,但是HDOJ放题目的时候,前面有个题目解释了什么是XXX定律。
    这里直接放了这个题目,肯定没几个人明白是干啥