1046 Shortest Distance

1046 Shortest Distance （20 分)

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 [3,10​5​​]), followed by N integer distances D​1​​ D​2​​ ⋯ 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 (≤10​4​​), 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 10​7​​.

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 9
3
1 3
2 5
4 1

Sample Output:

3
10
7

#include<set>
#include<map>
#include<list>
#include<queue>
#include<deque>
#include<cmath>
#include<stack>
#include<cstdio>
#include<string>
#include<bitset>
#include<vector>
#include<cstring>
#include<cstdlib>
#include<iostream>
#include<algorithm>
#include<bits/stdc++.h>
using namespace std;

#define e exp(1)
#define pp acos(-1)
#define mod 1000000007
#define inf 0x3f3f3f3f
#define ll long long
#define ull unsigned long long
#define mem(a,b) memset(a,b,sizeof(a))
int gcd(int a,int b) {
	return b?gcd(b,a%b):a;
}

const int maxn=2e5+5;

int a[maxn],sum[maxn]={0};
int main()
{
	ios::sync_with_stdio(false);
	int n;cin>>n;
	for(int i=1; i<=n; i++)
	{
		cin>>a[i];
		a[i+n]=a[i];
		sum[i]=sum[i-1]+a[i];
	}
	for(int i=n+1; i<=2*n; i++)sum[i]=sum[i-1]+a[i];
	int m;cin>>m;
	int x,y;
	while(m--)
	{
		int minx,sum1=0,sum2=0;
		cin>>x>>y;
		if(x==y)
		{
			cout<<0<<'\n';continue;
		}
		if(x>y)swap(x,y);
		
		sum1=sum[y-1]-sum[x-1];
		sum2=sum[x+n-1]-sum[y-1];
		minx=min(sum1,sum2);
		cout<<minx<<'\n';
	}
	return 0;
}