update

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

@@ -0,0 +1,25 @@
+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);
+ */

easy/326.power-of-three.go

@@ -0,0 +1,6 @@
+func isPowerOfThree(n int) bool {
+	if n <= 0 { // The power is non-negative.
+		return false
+	}
+	return 1162261467 % n == 0 // A magic number! (Actually, is the maximum of pow(3, x) in [1, 1<<32-1])
+}