1047. 删除字符串中的所有相邻重复项

class Solution:
    def removeDuplicates(self, s: str) -> str:
        stk = []
        for c in s:
            if stk and stk[-1] == c:
                stk.pop()
            else:
                stk.append(c)
        return ''.join(stk)

class Solution {
    public String removeDuplicates(String s) {
        StringBuilder sb = new StringBuilder();
        for (char c : s.toCharArray()) {
            if (sb.length() > 0 && sb.charAt(sb.length() - 1) == c) {
                sb.deleteCharAt(sb.length() - 1);
            } else {
                sb.append(c);
            }
        }
        return sb.toString();
    }
}

class Solution {
public:
    string removeDuplicates(string s) {
        string stk;
        for (char c : s) {
            if (!stk.empty() && stk[stk.size() - 1] == c) {
                stk.pop_back();
            } else {
                stk += c;
            }
        }
        return stk;
    }
};

func removeDuplicates(s string) string {
	stk := []rune{}
	for _, c := range s {
		if len(stk) > 0 && stk[len(stk)-1] == c {
			stk = stk[:len(stk)-1]
		} else {
			stk = append(stk, c)
		}
	}
	return string(stk)
}

impl Solution {
    pub fn remove_duplicates(s: String) -> String {
        let mut stack = Vec::new();
        for c in s.chars() {
            if !stack.is_empty() && *stack.last().unwrap() == c {
                stack.pop();
            } else {
                stack.push(c);
            }
        }
        stack.into_iter().collect()
    }
}

/**
 * @param {string} s
 * @return {string}
 */
var removeDuplicates = function (s) {
    const stk = [];
    for (const c of s) {
        if (stk.length && stk[stk.length - 1] == c) {
            stk.pop();
        } else {
            stk.push(c);
        }
    }
    return stk.join('');
};

char* removeDuplicates(char* s) {
    int n = strlen(s);
    char* stack = malloc(sizeof(char) * (n + 1));
    int i = 0;
    for (int j = 0; j < n; j++) {
        char c = s[j];
        if (i && stack[i - 1] == c) {
            i--;
        } else {
            stack[i++] = c;
        }
    }
    stack[i] = '\0';
    return stack;
}