LintCode_212 Space Replacement-优快云博客

本文介绍了一种将字符串中的空格替换为%20的算法实现。该算法使用字符数组而非字符串进行操作，并返回替换后的字符串长度。挑战在于实现原地替换。

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Write a method to replace all spaces in a string with %20. The string is given in a characters array, you can assume it has enough space for replacement and you are given the true length of the string.

You code should also return the new length of the string after replacement.

Notice

If you are using Java or Python，please use characters array instead of string.

Have you met this question in a real interview?

Yes

Example

Given "Mr John Smith", length = 13.

The string after replacement should be "Mr%20John%20Smith", you need to change the string in-place and return the new length 17.

Challenge

Do it in-place.

class Solution {
public:
    /**
     * @param string: An array of Char
     * @param length: The true length of the string
     * @return: The true length of new string
     */
    int replaceBlank(char string[], int length) {
        // Write your code here
        if (length == 0)
            return 0;
        int num_of_zero = 0;
        for (int i = 0; i < length; i++) {
            if (string[i] == ' ')
                num_of_zero++;
        }
        int new_len = length + 2 * num_of_zero;
        int res = new_len;
        string[new_len] = '\0';
        new_len--;
        for (int i = length - 1; i >= 0; i--) {
            if (string[i] == ' ') {
                string[new_len] = '0';
                new_len--;
                string[new_len] = '2';
                new_len--;
                string[new_len] = '%';
                new_len--;
            } else {
                string[new_len] = string[i];
                new_len--;
            }
        }
        return res;
    }
};