leetcode-go/easy/303.range-sum-query-immutable.go

type NumArray struct {
	sum []int
}


func Constructor(nums []int) (numArr NumArray) {
	n := len(nums)
	numArr.sum = make([]int, n+1)
	for i := 1; i <= n; i++ {
		numArr.sum[i] = numArr.sum[i-1] + nums[i-1]
	}
	return
}


func (this *NumArray) SumRange(i int, j int) int {
	return this.sum[j+1] - this.sum[i]
}


/**
 * Your NumArray object will be instantiated and called as such:
 * obj := Constructor(nums);
 * param_1 := obj.SumRange(i,j);
 */