Problem
Given an integer array nums, find the sum of the elements between indices i and j (i ≤ j), inclusive.
Note:
You may assume that the array does not change.
There are many calls to sumRange function.
Example
Given nums = [-2, 0, 3, -5, 2, -1]
sumRange(0, 2) -> 1
sumRange(2, 5) -> -1
sumRange(0, 5) -> -3
Code
static int var = [](){
std::ios::sync_with_stdio(false);
cin.tie(NULL);
return 0;
}();
class NumArray {
private:
vector<int> inner_nums;
public:
NumArray(vector<int> nums) {
int len = nums.size();
inner_nums.resize(len+1,0);
for(int i=0;i<len;i++)
inner_nums[i+1] = inner_nums[i]+nums[i];
}
int sumRange(int i, int j) {
return inner_nums[j+1] - inner_nums[i];
}
};
/**
* Your NumArray object will be instantiated and called as such:
* NumArray obj = new NumArray(nums);
* int param_1 = obj.sumRange(i,j);
*/
Result
303. Range Sum Query - Immutable.png
