PAT 甲级 1046. 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 <iostream>#include <vector>using namespace std;int main(){    int n;    cin>>n;    vector<int> dis(n+1);    int sum=0,right,left,m;    for(int i=1;i<=n;i++){        int temp;        cin>>temp;        sum+=temp;        dis[i]=sum;    }    cin>>m;    for(int i=0;i<m;i++){        cin>>right>>left;        if(right<left)            swap(right,left);        int temp=dis[right-1]-dis[left-1];        cout<<min(temp,sum-temp)<<endl;    }    return 0;}