2859. 计算 K 置位下标对应元素的和

2859. 计算 K 置位下标对应元素的和

• 难度: easy
• 原始链接: https://leetcode.cn/problems/sum-of-values-at-indices-with-k-set-bits
• 标签: 位运算

解法一: 位运算

go

func sumIndicesWithKSetBits(nums []int, k int) int {
  ans := 0
  for i, num := range nums {
    if countBit(i) == k {
      ans += num
    }
  }
  return ans
}

func countBit(num int) int {
  count := 0
  for num != 0 {
    count++
    num &= num - 1
  }
  return count
}