init commit

archive/algorithm/geektime/sort.go

@@ -0,0 +1,151 @@
+package geektime
+
+func bubble_1(arr []int) []int {
+	ret := make([]int, len(arr))
+	copy(ret, arr)
+	for i := range ret {
+		for j := range ret[i:] {
+			j = i + j
+			if ret[i] > ret[j] {
+				ret[i], ret[j] = ret[j], ret[i]
+			}
+		}
+	}
+	return ret
+}
+
+func bubble_2(arr []int) []int {
+	ret := make([]int, len(arr))
+	copy(ret, arr)
+	for i := range ret {
+		flag := false
+		for j := range ret[i:] {
+			j = i + j
+			if ret[i] > ret[j] {
+				flag = true
+				ret[i], ret[j] = ret[j], ret[i]
+			}
+		}
+		if !flag {
+			break
+		}
+	}
+	return ret
+}
+
+func insert(arr []int) []int {
+	ret := make([]int, len(arr))
+	copy(ret, arr)
+	for i := 1; i < len(ret); i++ {
+		val := ret[i]
+		j := i - 1
+		for ; j >= 0; j-- {
+			if ret[j] > val {
+				ret[j+1] = ret[j]
+			} else {
+				break
+			}
+		}
+		ret[j+1] = val
+	}
+	return ret
+}
+
+func selection(arr []int) []int {
+	ret := make([]int, len(arr))
+	copy(ret, arr)
+	for i := range ret {
+		min := i
+		for j := range ret[i:] {
+			j = i + j
+			if ret[min] > ret[j] {
+				min = j
+			}
+		}
+		ret[min], ret[i] = ret[i], ret[min]
+	}
+	return ret
+}
+
+//归并排序
+func merge_sort(arr []int) []int {
+	ret := make([]int, len(arr))
+	copy(ret, arr)
+	dichotomize(ret, 0, len(ret)-1)
+	return ret
+}
+
+func dichotomize(arr []int, i, j int) (int, int) {
+	if i >= j {
+		return i, j
+	}
+	i1, j1 := dichotomize(arr, i, (j-i)/2+i)
+	i2, j2 := dichotomize(arr, (j-i)/2+i+1, j)
+	merge(arr, i1, j1, i2, j2)
+	return i, j
+}
+
+func merge(arr []int, i1, j1, i2, j2 int) {
+	pos2 := i2
+	tmp := make([]int, j2-i1+1)
+	tmppos := 0
+	pos1 := i1
+	for ; pos1 <= j1 && pos2 <= j2; tmppos++ {
+		if arr[pos1] > arr[pos2] {
+			tmp[tmppos] = arr[pos2]
+			pos2++
+		} else {
+			tmp[tmppos] = arr[pos1]
+			pos1++
+		}
+	}
+	//剩余
+	if pos1 <= j1 {
+		for ; pos1 <= j1; pos1++ {
+			tmp[tmppos] = arr[pos1]
+			tmppos++
+		}
+	} else {
+		for ; pos2 <= j2; pos2++ {
+			tmp[tmppos] = arr[pos2]
+			tmppos++
+		}
+	}
+	//copy
+	tmppos = 0
+	for i := i1; i <= j2; i++ {
+		arr[i] = tmp[tmppos]
+		tmppos++
+	}
+}
+
+func qsort(arr []int) []int {
+	ret := make([]int, len(arr))
+	copy(ret, arr)
+	return qsort_c(ret)
+}
+
+func qsort_c(arr []int) []int {
+	n := len(arr)
+	if n == 2 {
+		if arr[0] > arr[1] {
+			arr[0], arr[1] = arr[1], arr[0]
+			return arr
+		}
+		return arr
+	} else if n <= 1 {
+		return arr
+	}
+	val := arr[n/2]
+	arr[0], arr[n/2] = arr[n/2], arr[0]
+	j := 1
+	for i := 1; i < n; i++ {
+		if arr[i] < val {
+			arr[i], arr[j] = arr[j], arr[i]
+			j++
+		}
+	}
+	qsort_c(arr[:j])
+	qsort_c(arr[j:])
+	return arr
+}