Create string-to-integer-atoi.go

Author: izharishaksa

string-to-integer-atoi.go

@@ -0,0 +1,56 @@
+package leetcode_solutions_golang
+
+import (
+	"math"
+	"strings"
+)
+
+//https://leetcode.com/problems/string-to-integer-atoi/
+func myAtoi(s string) int {
+	s = strings.Trim(s, " ")
+	if len(s) == 0 {
+		return 0
+	}
+	isNegative := false
+	index := -1
+	isStarted := false
+	if !(s[0] == '-' || (s[0] >= '0' && s[0] <= '9') || s[0] == '+' || s[0] == ' ') {
+		isStarted = true
+	}
+	for i := 0; i < len(s) && !isStarted; i++ {
+		if s[i] == '-' {
+			isStarted = true
+			isNegative = true
+			index = i + 1
+		}
+		if s[i] == '+' {
+			isStarted = true
+			index = i + 1
+		}
+		if s[i] >= '0' && s[i] <= '9' {
+			index = i
+			isStarted = true
+		}
+	}
+	if index < 0 {
+		return 0
+	}
+	result := int64(0)
+	for i := index; i < len(s); i++ {
+		if s[i] >= '0' && s[i] <= '9' {
+			result = result*10 + int64(s[i]-'0')
+			if !isNegative && result > math.MaxInt32 {
+				result = math.MaxInt32
+			}
+			if isNegative && result > math.MaxInt32+1 {
+				result = math.MaxInt32 + 1
+			}
+		} else {
+			break
+		}
+	}
+	if isNegative {
+		result = -result
+	}
+	return int(result)
+}