/**
* https://leetcode.com/articles/range-sum-query-immutable/
*/
public class NumArray {
private int[] sums;
public NumArray(int[] nums) {
sums = new int[nums.length];
for (int i = 0; i < nums.length; i++) {
sums[i] = nums[i] + (i > 0 ? sums[i - 1] : 0);
}
}
public int sumRange(int i, int j) {
return sums[j] - (i > 0 ? sums[i - 1] : 0);
}
}
// Your NumArray object will be instantiated and called as such:
// NumArray numArray = new NumArray(nums);
// numArray.sumRange(0, 1);
// numArray.sumRange(1, 2);