CodeForces599APatrick and Shopping（数学，简易版最短路）

Description
Today Patrick waits for a visit from his friend Spongebob. To prepare for the visit, Patrick needs to buy some goodies in two stores located near his house. There is a d1 meter long road between his house and the first shop and a d2 meter long road between his house and the second shop. Also, there is a road of length d3 directly connecting these two shops to each other. Help Patrick calculate the minimum distance that he needs to walk in order to go to both shops and return to his house.

Patrick always starts at his house. He should visit both shops moving only along the three existing roads and return back to his house. He doesn’t mind visiting the same shop or passing the same road multiple times. The only goal is to minimize the total distance traveled.

Input
The first line of the input contains three integers d1, d2, d3 (1 ≤ d1, d2, d3 ≤ 108) — the lengths of the paths.

d1 is the length of the path connecting Patrick’s house and the first shop;
d2 is the length of the path connecting Patrick’s house and the second shop;
d3 is the length of the path connecting both shops.
Output
Print the minimum distance that Patrick will have to walk in order to visit both shops and return to his house.

Sample Input
Input
10 20 30
Output
60
Input
1 1 5
Output
4
代码：

#include<stdio.h>int min(int x,int y){    return x<y?x:y;}int main(){    int a,b,c;    int mi[10];    while(scanf("%d %d %d",&a,&b,&c)!=EOF)    {        mi[1]=min(a,b+c);        mi[2]=min(b,a+c);        mi[3]=min(a+b,c);        printf("%d\n",mi[1]+mi[2]+mi[3]);    }    return 0;}

思路：题目是一个人要去两个超市最后返回，给你三点之间的路径问你怎么走才最近。这道题求出三个最短的路就行了。他家到a超市最短路，他家到b超市最短路，a超市到b超市最短路。三个数之和即为所求。（因为他肯定要到a和b超市，不管先到哪个都要去另一个然后从另一个返回家，所以求出这三个最短路就行了）