LeetCode:307. 區域和檢索 - 數組可修改

class NumArray {
public:
    vector<int> num;
    NumArray(vector<int>& nums) {
        num=nums;
    }
    
    void update(int i, int val) {
        num[i]=val;
    }
    
    int sumRange(int i, int j) {
        return accumulate(num.begin()+i,num.begin()+1+j,0);
    }
};

/**
 * Your NumArray object will be instantiated and called as such:
 * NumArray* obj = new NumArray(nums);
 * obj->update(i,val);
 * int param_2 = obj->sumRange(i,j);
 */