[Swift]LeetCode1176. 健身计划评估 | Diet Plan Performance

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A dieter consumes calories[i] calories on the i-th day.  For every consecutive sequence of k days, they look at T, the total calories consumed during that sequence of k days:

• If T < lower, they performed poorly on their diet and lose 1 point; 
• If T > upper, they performed well on their diet and gain 1 point;
• Otherwise, they performed normally and there is no change in points.

Return the total number of points the dieter has after all calories.length days.

Note that: The total points could be negative.

Example 1:

Input: calories = [1,2,3,4,5], k = 1, lower = 3, upper = 3
Output: 0
Explaination: calories[0], calories[1] < lower and calories[3], calories[4] > upper, total points = 0.

Example 2:

Input: calories = [3,2], k = 2, lower = 0, upper = 1
Output: 1
Explaination: calories[0] + calories[1] > upper, total points = 1.

Example 3:

Input: calories = [6,5,0,0], k = 2, lower = 1, upper = 5
Output: 0
Explaination: calories[0] + calories[1] > upper, calories[2] + calories[3] < lower, total points = 0.

Constraints:

• 1 <= k <= calories.length <= 10^5
• 0 <= calories[i] <= 20000
• 0 <= lower <= upper

---

你的好友是一位健身爱好者。前段日子，他给自己制定了一份健身计划。现在想请你帮他评估一下这份计划是否合理。

他会有一份计划消耗的卡路里表，其中 calories[i] 给出了你的这位好友在第 i 天需要消耗的卡路里总量。

计划的统计周期通常是 k 天，你需要计算他在每一段连续的 k 天内消耗的总卡路里 T：

• 如果 T < lower，那么这份计划相对糟糕，并失去 1 分； 
• 如果 T > upper，那么这份计划相对优秀，并获得 1 分；
• 否则，这份计划普普通通，分值不做变动。

请返回统计完所有 calories.length 天后得到的总分作为评估结果。

注意：总分可能是负数。

示例 1：

输入：calories = [1,2,3,4,5], k = 1, lower = 3, upper = 3
输出：0
解释：calories[0], calories[1] < lower 而 calories[3], calories[4] > upper, 总分 = 0.

示例 2：

输入：calories = [3,2], k = 2, lower = 0, upper = 1
输出：1
解释：calories[0] + calories[1] > upper, 总分 = 1.

示例 3：

输入：calories = [6,5,0,0], k = 2, lower = 1, upper = 5
输出：0
解释：calories[0] + calories[1] > upper, calories[2] + calories[3] < lower, 总分 = 0.

提示：

• 1 <= k <= calories.length <= 10^5
• 0 <= calories[i] <= 20000
• 0 <= lower <= upper

---

Runtime: 220 ms

Memory Usage: 22.5 MB

class Solution {
    func dietPlanPerformance(_ calories: [Int], _ k: Int, _ lower: Int, _ upper: Int) -> Int {
        var n:Int = calories.count
        var sum:Int = 0
        var ans:Int = 0
        for i in 0..<n
        {
            sum += calories[i]
            if i >= k
            {
                sum -= calories[i-k]
            }
            if i >= k-1
            {
                if sum > upper
                {
                    ans += 1
                }
                else if sum < lower
                {
                    ans -= 1
                }
            }
        }
        return ans
    }
}

---

224ms

class Solution {
    func dietPlanPerformance(_ calories: [Int], _ k: Int, _ lower: Int, _ upper: Int) -> Int {
        guard calories.count > 0 && k >= 1 else { return 0 }
                
        var res = 0
        var sum = 0
        
        var i = -1
        var j = 0
        for j in 0..<calories.count {
            sum += calories[j]

            if j - i > k {
                i += 1
                sum -= calories[i]                
            }

            if j - i < k { continue }
            
            if sum < lower { res -= 1 }
            else if sum > upper { res += 1 }   
        }
        
        return res
    }
}

---

228ms

class Solution {
    func dietPlanPerformance(_ calories: [Int], _ k: Int, _ lower: Int, _ upper: Int) -> Int {
        
        var i = 0 
        var result = 0
        var sum = 0
        while i < calories.count {
            sum += calories[i]
            if i < k { 
                if i == k - 1 {
                    if sum > upper { result += 1 }
                    if sum < lower { result -= 1 }
                }
                i += 1
                continue 
            } else {
                // print(sum)
                sum -= calories[i - k]
            }
            if sum > upper { result += 1 }
            if sum < lower { result -= 1 }
            i += 1
        }
        return result
    }
}

---

232ms

class Solution {
    func dietPlanPerformance(_ calories: [Int], _ k: Int, _ lower: Int, _ upper: Int) -> Int {
        guard calories.count >= k else {
            return 0
        }
        func getScore(_ costCalories:  Int)  -> Int {
            if costCalories < lower {
                return -1
            }
            if  costCalories > upper {
                return 1
            }
            return 0
        }
        var ans = 0
        var i = 0
        var tempCalories = 0
        while i < k {
            tempCalories += calories[i]
            i += 1
        }
        ans += getScore(tempCalories)
        while i < calories.count {
            tempCalories += (calories[i] - calories[i -  k])
            ans += getScore(tempCalories)
            i += 1
        }
        return ans
    }
}

---

236ms

class Solution {
    func dietPlanPerformance(_ calories: [Int], _ k: Int, _ lower: Int, _ upper: Int) -> Int {
        var totalPoints = 0
        var preKSum: Int? = nil
        for i in k-1 ..< calories.count {
            if var kSum = preKSum {
                preKSum = kSum - calories[i-k] + calories[i]
            } else {
                preKSum = calories[0..<k].reduce(0,+)
            }
            
            if preKSum! < lower {
                totalPoints -= 1
            } else if preKSum! > upper {
                totalPoints += 1
            }
        }
        
        return totalPoints
    }
}