2960-CountTestedDevicesAfterTestOperations.go

package main

// 2960. Count Tested Devices After Test Operations
// You are given a 0-indexed integer array batteryPercentages having length n, denoting the battery percentages of n 0-indexed devices.
// Your task is to test each device i in order from 0 to n - 1, by performing the following test operations:
//     If batteryPercentages[i] is greater than 0:
//         Increment the count of tested devices.
//         Decrease the battery percentage of all devices with indices j in the range [i + 1, n - 1] by 1, ensuring their battery percentage never goes below 0, i.e, batteryPercentages[j] = max(0, batteryPercentages[j] - 1).
//         Move to the next device.
//     Otherwise, move to the next device without performing any test.

// Return an integer denoting the number of devices that will be tested after performing the test operations in order.

// Example 1:
// Input: batteryPercentages = [1,1,2,1,3]
// Output: 3
// Explanation: Performing the test operations in order starting from device 0:
// At device 0, batteryPercentages[0] > 0, so there is now 1 tested device, and batteryPercentages becomes [1,0,1,0,2].
// At device 1, batteryPercentages[1] == 0, so we move to the next device without testing.
// At device 2, batteryPercentages[2] > 0, so there are now 2 tested devices, and batteryPercentages becomes [1,0,1,0,1].
// At device 3, batteryPercentages[3] == 0, so we move to the next device without testing.
// At device 4, batteryPercentages[4] > 0, so there are now 3 tested devices, and batteryPercentages stays the same.
// So, the answer is 3.

// Example 2:
// Input: batteryPercentages = [0,1,2]
// Output: 2
// Explanation: Performing the test operations in order starting from device 0:
// At device 0, batteryPercentages[0] == 0, so we move to the next device without testing.
// At device 1, batteryPercentages[1] > 0, so there is now 1 tested device, and batteryPercentages becomes [0,1,1].
// At device 2, batteryPercentages[2] > 0, so there are now 2 tested devices, and batteryPercentages stays the same.
// So, the answer is 2.
 
// Constraints:
//     1 <= n == batteryPercentages.length <= 100
//     0 <= batteryPercentages[i] <= 100

import "fmt"

func countTestedDevices(batteryPercentages []int) int {
    res := 0
    for _, v := range batteryPercentages {
        if v > res {
            res++
        }
    }
    return res 
}

func countTestedDevices1(batteryPercentages []int) int {
    res := 0
    // 如果 batteryPercentages[i] 大于 0：
    //     增加 已测试设备的计数。
    //     将下标在 [i + 1, n - 1] 的所有设备的电池百分比减少 1，确保它们的电池百分比 不会低于 0 ，即 batteryPercentages[j] = max(0, batteryPercentages[j] - 1)。
    //     移动到下一个设备。
    // 否则，移动到下一个设备而不执行任何测试。
    for _,v := range batteryPercentages {
        if v - res > 0 { // 电量不足直接跳过
            res++ // 每测试一设置设备  下标在 [i + 1, n - 1] 的所有设备的电池百分比减少 1 
        }
    }
    return res
}

func main() {
    // Example 1:
    // Input: batteryPercentages = [1,1,2,1,3]
    // Output: 3
    // Explanation: Performing the test operations in order starting from device 0:
    // At device 0, batteryPercentages[0] > 0, so there is now 1 tested device, and batteryPercentages becomes [1,0,1,0,2].
    // At device 1, batteryPercentages[1] == 0, so we move to the next device without testing.
    // At device 2, batteryPercentages[2] > 0, so there are now 2 tested devices, and batteryPercentages becomes [1,0,1,0,1].
    // At device 3, batteryPercentages[3] == 0, so we move to the next device without testing.
    // At device 4, batteryPercentages[4] > 0, so there are now 3 tested devices, and batteryPercentages stays the same.
    // So, the answer is 3.
    fmt.Println(countTestedDevices([]int{1,1,2,1,3})) // 3
    // Example 2:
    // Input: batteryPercentages = [0,1,2]
    // Output: 2
    // Explanation: Performing the test operations in order starting from device 0:
    // At device 0, batteryPercentages[0] == 0, so we move to the next device without testing.
    // At device 1, batteryPercentages[1] > 0, so there is now 1 tested device, and batteryPercentages becomes [0,1,1].
    // At device 2, batteryPercentages[2] > 0, so there are now 2 tested devices, and batteryPercentages stays the same.
    // So, the answer is 2.
    fmt.Println(countTestedDevices([]int{0,1,2})) // 2

    fmt.Println(countTestedDevices1([]int{1,1,2,1,3})) // 3
    fmt.Println(countTestedDevices1([]int{0,1,2})) // 2
}