80 lines
2.2 KiB
Java
80 lines
2.2 KiB
Java
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//给你一个字符串 s ，请你去除字符串中重复的字母，使得每个字母只出现一次。需保证 返回结果的字典序最小（要求不能打乱其他字符的相对位置）。
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//
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// 注意：该题与 1081 https://leetcode-cn.com/problems/smallest-subsequence-of-distinct
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//-characters 相同
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//
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//
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//
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// 示例 1：
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//
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//
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//输入：s = "bcabc"
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//输出："abc"
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//
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//
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// 示例 2：
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//
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//
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//输入：s = "cbacdcbc"
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//输出："acdb"
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//
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//
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//
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// 提示：
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//
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//
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// 1 <= s.length <= 104
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// s 由小写英文字母组成
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//
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// Related Topics 栈 贪心算法 字符串
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// 👍 518 👎 0
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package leetcode.editor.cn;
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import java.util.Stack;
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//316:去除重复字母
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public class RemoveDuplicateLetters {
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public static void main(String[] args) {
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//测试代码
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Solution solution = new RemoveDuplicateLetters().new Solution();
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System.out.println(solution.removeDuplicateLetters("bcabc"));//abc
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}
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//力扣代码
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//leetcode submit region begin(Prohibit modification and deletion)
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class Solution {
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public String removeDuplicateLetters(String s) {
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boolean[] vis = new boolean[26];
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int[] num = new int[26];
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for (int i = 0; i < s.length(); i++) {
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num[s.charAt(i) - 'a']++;
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}
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Stack<Character> stack = new Stack<>();
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for (int i = 0; i < s.length(); i++) {
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char ch = s.charAt(i);
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if (!vis[ch - 'a']) {
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while (!stack.empty() && stack.peek() > ch) {
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if (num[stack.peek() - 'a'] > 0) {
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vis[stack.peek() - 'a'] = false;
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stack.pop();
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} else {
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break;
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}
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}
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vis[ch - 'a'] = true;
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stack.push(ch);
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}
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num[ch - 'a'] -= 1;
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}
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StringBuilder sBuilder = new StringBuilder();
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while (!stack.empty()) {
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sBuilder.insert(0, stack.pop());
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}
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s = sBuilder.toString();
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return s;
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}
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}
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//leetcode submit region end(Prohibit modification and deletion)
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}
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