题目描述
include [HTML_REMOVED]
include [HTML_REMOVED]
include [HTML_REMOVED]
include [HTML_REMOVED]
include [HTML_REMOVED]
using namespace std;
int n,m;
const int N = 1e5+10;
int arr1[N],arr2[N];
//前缀和求某一段区间和
int main(int argc, char** argv) {
cin>>n>>m;
for(int i=1;i<=n;i){
cin>>arr1[i];
}
for(int j=1;j<=n;j){
arr2[j] = arr2[j-1]+arr1[j];
}
while(m–){
int left,right;
cin>>left>>right;
cout<<arr2[right] - arr2[left-1]<<endl;
}
return 0;
}
样例
blablabla
算法1
(暴力枚举) $O(n^2)$
blablabla
时间复杂度
参考文献
C++ 代码
blablabla
算法2
(暴力枚举) $O(n^2)$
blablabla
时间复杂度
参考文献
C++ 代码
blablabla