Kotlin练习 之使用Kotlin实现:二分查找,选择排序,冒泡排序,快速排序

Kotlin练习之 使用Kotlin实现:二分查找,选择排序,冒泡排序,快速排序

最近开始接触学习kotlin,于是决定动手写一些相对简单的代码.
感觉kotlin没有像java那样的for(int i = 0;i< arr.length;i++)这样的循环还是很不方便的.

• 二分查找

    private fun binaryTest(arrs: IntArray, target: Int): Int {
        var start: Int = 0;
        var end: Int = arrs.size - 1;
        while (start <= end) {
            var middle: Int = (start + end) / 2;
            if (arrs.get(middle) == target) {
                return middle;
            } else if (arrs.get(middle) < target) {
                start = middle + 1
            } else if (arrs.get(middle) > target) {
                end = middle - 1;
            }
        }
        return -1;
    }

---

• 选择排序:

 private fun selectSort(arrs: IntArray) {
        var outIndex: Int = 0
        var inIndex: Int = 0
        var minIndex: Int = 0
        while (outIndex < arrs.size - 1) {
            inIndex = outIndex + 1
            minIndex = outIndex
            while (inIndex < arrs.size) {
                if (arrs[minIndex] > arrs[inIndex]) {
                    minIndex = inIndex
                }
                inIndex++
            }
            if (minIndex != outIndex) {
                var temp: Int = arrs[outIndex]
                arrs[outIndex] = arrs[minIndex]
                arrs[minIndex] = temp
            }
            outIndex++
        }
    }

---

• 冒泡排序:

 private fun bubbleSort(arrs: IntArray) {
        var outIndex: Int = 0
        var inIndex: Int = 0
        var temp: Int = 0
        while (outIndex < arrs.size) {
            inIndex = outIndex + 1;
            while (inIndex < arrs.size) {
                if (arrs[outIndex] > arrs[inIndex]) {
                    temp = arrs[outIndex]
                    arrs[outIndex] = arrs[inIndex]
                    arrs[inIndex] = temp
                }
                inIndex++
            }
            outIndex++
        }
    }

---

• 快速排序:

 private fun quickSort(arrs: IntArray, lowStart: Int, highEnd: Int) {
        var low: Int = lowStart
        var high: Int = highEnd
        var povit: Int = arrs[low]

        while (low < high) {
            while (low < high && arrs[high] >= povit) {
                high--
            }
            if (low < high) {
                var temp: Int = arrs[high]
                arrs[high] = arrs[low]
                arrs[low] = temp
                low++
            }
            while (low < high && arrs[low] <= povit) {
                low++
            }
            if (low < high) {
                var temp: Int = arrs[high]
                arrs[high] = arrs[low]
                arrs[low] = temp
                high--
            }
        }
        if (low > lowStart) quickSort(arrs, lowStart, low - 1)
        if (high < highEnd) quickSort(arrs, low + 1, highEnd)
    }

---

• 打印方法:

    private fun logArray(arrs: IntArray) {
        var sb: StringBuilder = StringBuilder();
        for ((index, value) in arrs.withIndex()) {
            if (index == 0) {
                sb.append("[ ").append(value).append(", ")
            } else if (index == arrs.size - 1) {
                sb.append(value).append("]")
            } else {
                sb.append(value).append(", ")
            }
        }
        Log.e(TAG, sb.toString())
    }

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测试代码地址