add sol

leetcode/leetcode75/724.FindPivotIndex/findPivotIndex.go

@@ -0,0 +1,44 @@
+package main
+
+import (
+	"fmt"
+)
+
+func pivotIndex(nums []int) int {
+	sum := 0
+	for i := 0; i < len(nums); i++ {
+		sum += nums[i]
+	}
+
+	leftSum, rightSum := 0, 0
+	for i := 0; i < len(nums); i++ {
+		rightSum = sum - nums[i] - leftSum
+		if leftSum == rightSum {
+			return i
+		}
+		leftSum += nums[i]
+	}
+
+	return -1
+}
+
+func pivotIndex1(nums []int) int {
+	prefix := make([]int, len(nums))
+	prefix[0] = nums[0]
+
+	for i := 1; i < len(nums); i++ {
+		prefix[i] = prefix[i-1] + nums[i]
+	}
+
+	for i := 0; i < len(nums); i++ {
+		if prefix[i] == prefix[len(nums)-1]-prefix[i]+nums[i] {
+			return i
+		}
+	}
+	return -1
+}
+
+func main() {
+	nums := []int{1, 7, 3, 6, 5, 6}
+	fmt.Println(pivotIndex(nums))
+}