2834. 找出美丽数组的最小和

找出美丽数组的最小和

• 难度: medium
• 原始链接: https://leetcode.cn/problems/find-the-minimum-possible-sum-of-a-beautiful-array
• 标签: 数学

解法一: 数学

go

const MOD = 1000000007

func minimumPossibleSum(n int, target int) int {
  // 左边部分
  left1 := 1
  right1 := min(target>>1, n)
  leftSum := ((left1 + right1) * (right1 - left1 + 1)) >> 1
  // 右边部分
  left2 := target
  right2 := target + (n - (right1 - left1 + 1)) - 1
  rightSum := ((left2 + right2) * (right2 - left2 + 1)) >> 1
  return (leftSum + rightSum) % MOD
}