✨ Added solution to 747

Sathish Babu · Sathish Babu · commit 5060bbfbcd2f · 2020-06-04T18:00:24.000+05:30
diff --git a/src/0747.Largest-Number-At-Least-Twice-of-Others/README.md b/src/0747.Largest-Number-At-Least-Twice-of-Others/README.md
@@ -5,11 +5,27 @@
 
 ## Description
 
+In a given integer array nums, there is always exactly one largest element.
+
+Find whether the largest element in the array is at least twice as much as every other number in the array.
+
+If it is, return the index of the largest element, otherwise return -1.
+
+**Example 1:**
+
+```
+Input: nums = [3, 6, 1, 0]
+Output: 1
+Explanation: 6 is the largest integer, and for every other number in the array x,
+6 is more than twice as big as x.  The index of value 6 is 1, so we return 1.
+```
+
 **Example 1:**
 
 ```
-Input: a = "11", b = "1"
-Output: "100"
+Input: nums = [1, 2, 3, 4]
+Output: -1
+Explanation: 4 isn't at least as big as twice the value of 3, so we return -1.
 ```
 
 ## 题意
diff --git a/src/0747.Largest-Number-At-Least-Twice-of-Others/Solution.go b/src/0747.Largest-Number-At-Least-Twice-of-Others/Solution.go
@@ -1,5 +1,20 @@
 package Solution
 
-func Solution(x bool) bool {
-	return x
+func Solution(nums []int) int {
+	n := len(nums)
+	if n == 1 {
+		return 0
+	}
+	max, maxIndex := -1, -1
+	for i, num := range nums {
+		if num > max {
+			max, maxIndex = num, i
+		}
+	}
+	for _, num := range nums {
+		if num != max && 2*num > max {
+			return -1
+		}
+	}
+	return maxIndex
 }
diff --git a/src/0747.Largest-Number-At-Least-Twice-of-Others/Solution_test.go b/src/0747.Largest-Number-At-Least-Twice-of-Others/Solution_test.go
@@ -10,12 +10,12 @@ func TestSolution(t *testing.T) {
 	//	测试用例
 	cases := []struct {
 		name   string
-		inputs bool
-		expect bool
+		inputs []int
+		expect int
 	}{
-		{"TestCase", true, true},
-		{"TestCase", true, true},
-		{"TestCase", false, false},
+		{"TestCase", []int{3, 6, 1, 0}, 1},
+		{"TestCase", []int{1, 2, 3, 4}, -1},
+		{"TestCase", []int{6}, 0},
 	}
 
 	//	开始测试
