[LeetCode] 246. Strobogrammatic Number

whatsns 发布于2019-08-19 11:14 / 1121人阅读

Problem

A strobogrammatic number is a number that looks the same when rotated 180 degrees (looked at upside down).

Write a function to determine if a number is strobogrammatic. The number is represented as a string.

Example 1:

Input: "69"
Output: true
Example 2:

Input: "88"
Output: true
Example 3:

Input: "962"
Output: false

Solution

class Solution {
    public boolean isStrobogrammatic(String s) {
        //69, 88, 00, 11, 6969, 698869, 69869, 6908069, 886988
        Map map = new HashMap<>();
        map.put("6", "9");
        map.put("9", "6");
        map.put("0", "0");
        map.put("1", "1");
        map.put("8", "8");
        int i = 0, j = s.length()-1;
        while (i <= j) {
            if (!map.containsKey(s.charAt(i))) return false;
            if (map.get(s.charAt(i++)) != s.charAt(j--)) return false;
        }
        return true;
    }
}

云服务器私有云 Strobogrammatic LeetCode h246 linux 246

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