String to Integer

Similar Problems:
Description
Given a string, convert it to an integer. You may assume the string is a valid integer number that can be presented by a signed 32bit integer (-2^31 ~ 2^31-1).
Example
Given “123”, return 123.
Github: code.dennyzhang.com
Credits To: lintcode.com
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- Solution:
// Blog link: https://code.dennyzhang.com/string-to-integer // Basic Ideas: // Complexity: Time O(1), Space O(1) /** * @param str: A string * @return: An integer */ func stringToInteger (str string) int { res := 0 negative := false for i, ch := range str { if i == 0 && ch == '-' { negative = true continue } res = res*10 + int(ch-'0') } if negative { res = -res } return res }
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