统计「优美子数组」

Posted 2021-02-27 ybf-yyj

1、试题地址：https://leetcode-cn.com/problems/count-number-of-nice-subarrays/submissions/
2、试题思路：

3、试题代码

package main

import (
    "fmt"
)

func main() {
    // nums := []int{2, 4, 6}
    nums := []int{1, 2, 3, 1, 2, 4, 1, 2, 3, 2, 1, 3}
    fmt.Println(numberOfSubarrays(nums, 4))
}

//试题地址：https://leetcode-cn.com/problems/count-number-of-nice-subarrays/submissions/
func numberOfSubarrays(nums []int, k int) int {
    num, i, j, sum, temp := 0, 0, -1, 0, 0
    for ; i < len(nums); i++ { //找出第一个符合的数组
        if nums[i]%2 == 1 {
            sum++
        }
        if sum == k {
            j = i
            break
        }
    }
    if j == -1 { //数组中的奇数总个数小于k个
        return num
    }
    // fmt.Println(nums, j)
    i = 0
    flag := true
    for i < len(nums) {
        for {
            if sum > k {
                sum-- //回溯
                break
            }
            if sum == k {
                fmt.Println(i, j)
                if flag {
                    temp = j //记住j的上一个基数位置
                    flag = false
                }
                num++
            }
            j++
            if j >= len(nums) {
                break
            }
            sum += nums[j] % 2
        }
        if j >= len(nums) && nums[i]%2 == 1 { //保证这是最后一个
            break
        }
        sum -= nums[i] % 2
        j = temp
        flag = true
        i++
    }
    return num
}

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