PAT A1046. Shortest Distance (20)

The task is really simple: given N exits on a highway which forms a simple cycle, you are supposed to tell the shortest distance between any pair of exits.

Input Specification:

Each input file contains one test case. For each case, the first line contains an integer N (in [3, 10⁵]), followed by N integer distances D₁ D₂ ... D_N, where D_i is the distance between the i-th and the (i+1)-st exits, and D_N is between the N-th and the 1st exits. All the numbers in a line are separated by a space. The second line gives a positive integer M (<=10⁴), with M lines follow, each contains a pair of exit numbers, provided that the exits are numbered from 1 to N. It is guaranteed that the total round trip distance is no more than 10⁷.

Output Specification:

For each test case, print your results in M lines, each contains the shortest distance between the corresponding given pair of exits.

Sample Input:

5 1 2 4 14 931 32 54 1

Sample Output:

3107

#include <cstdio>#include <algorithm>#define Max 100010using namespace std;int main(){int n,v[Max]={0},sum[Max]={0};scanf("%d",&n);for(int i=1;i<=n;i++){scanf("%d",&v[i]);sum[i+1]=sum[i]+v[i];}int m;scanf("%d",&m);for(int j=0;j<m;j++){int a,b,l1=0,l2=0;scanf("%d%d",&a,&b);int flag;    if(a>b)     {    flag =a ;    a=b;    b=flag;     }l1=sum[b]-sum[a];l2=sum[n+1]-l1;if(l1>l2)     {    flag =l1 ;    l1=l2;    b=flag;     }printf("%d\n",l1);}    system("pause");    return 0;}