提交origin2.0版本

util/rand/rand.go

@@ -0,0 +1,91 @@
+package rand
+
+import (
+	"math/rand"
+	"time"
+)
+
+func init() {
+	rand.Seed(time.Now().UnixNano())
+}
+
+func RandGroup(p ...uint32) int {
+	if p == nil {
+		panic("args not found")
+	}
+
+	r := make([]uint32, len(p))
+	for i := 0; i < len(p); i++ {
+		if i == 0 {
+			r[0] = p[0]
+		} else {
+			r[i] = r[i-1] + p[i]
+		}
+	}
+
+	rl := r[len(r)-1]
+	if rl == 0 {
+		return 0
+	}
+
+	rn := uint32(rand.Int63n(int64(rl)))
+	for i := 0; i < len(r); i++ {
+		if rn < r[i] {
+			return i
+		}
+	}
+
+	panic("bug")
+}
+
+func RandInterval(b1, b2 int32) int32 {
+	if b1 == b2 {
+		return b1
+	}
+
+	min, max := int64(b1), int64(b2)
+	if min > max {
+		min, max = max, min
+	}
+	return int32(rand.Int63n(max-min+1) + min)
+}
+
+func RandIntervalN(b1, b2 int32, n uint32) []int32 {
+	if b1 == b2 {
+		return []int32{b1}
+	}
+
+	min, max := int64(b1), int64(b2)
+	if min > max {
+		min, max = max, min
+	}
+	l := max - min + 1
+	if int64(n) > l {
+		n = uint32(l)
+	}
+
+	r := make([]int32, n)
+	m := make(map[int32]int32)
+	for i := uint32(0); i < n; i++ {
+		v := int32(rand.Int63n(l) + min)
+
+		if mv, ok := m[v]; ok {
+			r[i] = mv
+		} else {
+			r[i] = v
+		}
+
+		lv := int32(l - 1 + min)
+		if v != lv {
+			if mv, ok := m[lv]; ok {
+				m[v] = mv
+			} else {
+				m[v] = lv
+			}
+		}
+
+		l--
+	}
+
+	return r
+}