Leetcode-303 Range Sum Query - Immutable(区域和检索 - 数组不可变)

class NumArray
{
    public:
        vector<int> input;
        vector<int> dp;
        NumArray(vector<int> nums)
        {
            input = nums;
            dp.push_back(nums[0]);
            for(int i = 1;i < nums.size();i ++)
            {
                dp.push_back(dp[i-1]+nums[i]);
            }
        }

        int sumRange(int i, int j)
        {
            return dp[j]-dp[i]+input[i];
        }
};