···

include[HTML_REMOVED]

include[HTML_REMOVED]

include[HTML_REMOVED]

include[HTML_REMOVED]

using namespace std;
const int N=1e5+10;
int n,m;
int A[N],B[N];
int main(){
int n,m;
scanf(“%d%d”,&n,&m);
for(int i=1;i<=n;i) scanf(“%d”,&A[i]); //确保s【0】是0
for(int i=1;i<=n;i) B[i]=B[i-1]+A[i]; //构造一个前缀和的数列 实现O1时间取值的复杂度
while(m–){
int l,r;
cin>>l>>r;
printf(“%d\n”,B[r]-B[l-1]); //计算区间和构造前缀和
}
return 0;

}
···