#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <algorithm>
#include <vector>
#include <stack>
#include <queue>
#include <cstring>
#include <cmath>
#include <map>
#define LL long long
#define pb push_back
#define mp make_pair
using namespace std;
#define INF 1e9
const int MAXN = 100005;

LL c[MAXN];

int lowbit(int n){
    return n&(-n);
}

void update(int p, LL val){
    while(p<MAXN){
        c[p] += val;
        p += lowbit(p);
    }
}

LL Sum(int p){
    LL sum = 0;
    while(p>0){
        sum += c[p];
        p -= lowbit(p);
    }
    return sum;
}

int main(){
    int T;
    int n,m;
    int i,j;
    int a,b;
    LL p;
    scanf("%d", &T);
    while(T--){
        scanf("%d%d", &n, &m);
        memset(c,0,sizeof(c));
        for(i=1; i<n; ++i){
            scanf("%I64d", &p);
            update(i,p);
        }
        for(i=0; i<m; ++i){
            j = i%n+1;
            scanf("%d%d", &a, &b);
            LL sum = 0;
            if(a < b){
                if(a < j){
                    sum += 2*Sum(n-1);
                    sum -= Sum(j-1);
                    sum += Sum(b-1);
                }
                else{
                    sum += Sum(b-1);
                    sum -= Sum(j-1);
                }
            }
            else{
                sum += 2*Sum(n-1);
                sum -= Sum(j-1);
                sum -= Sum(b-1);
            }
            printf("%I64d\n", sum);
        }
    }
    return 0;
}