69 accepted, 6ms. The fastest is 3ms.

Author: aQua

Algorithms/0069.sqrtx/README.md

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+# [69. Sqrt(x)](https://leetcode.com/problems/sqrtx/)
+
+## 题目
+Implement int sqrt(int x).
+
+Compute and return the square root of x.
+
+## 解题思路
+
+见程序注释

Algorithms/0069.sqrtx/sqrtx.go

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+package Problem0069
+
+func mySqrt(x int) int {
+	res := 1
+	for !(res*res <= x && x < (res+1)*(res+1)) {
+		res = (res + x/res) / 2
+	}
+
+	return res
+}

Algorithms/0069.sqrtx/sqrtx_test.go

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+package Problem0069
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+type question struct {
+	para
+	ans
+}
+
+// para 是参数
+type para struct {
+	x int
+}
+
+// ans 是答案
+type ans struct {
+	one int
+}
+
+func Test_Problem0069(t *testing.T) {
+	ast := assert.New(t)
+
+	qs := []question{
+
+		question{
+			para{
+				15,
+			},
+			ans{
+				3,
+			},
+		},
+
+		question{
+			para{
+				3,
+			},
+			ans{
+				1,
+			},
+		},
+
+		question{
+			para{
+				9,
+			},
+			ans{
+				3,
+			},
+		},
+
+		// 如需多个测试，可以复制上方元素。
+	}
+
+	for _, q := range qs {
+		a, p := q.ans, q.para
+		fmt.Printf("~~%v~~\n", p)
+
+		ast.Equal(a.one, mySqrt(p.x), "输入:%v", p)
+	}
+}