101 lines
3.0 KiB
Java
101 lines
3.0 KiB
Java
//返回 s 字典序最小的子序列，该子序列包含 s 的所有不同字符，且只包含一次。
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//
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// 注意：该题与 316 https://leetcode.com/problems/remove-duplicate-letters/ 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 <= 1000
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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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// 👍 95 👎 0
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package leetcode.editor.cn;
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import java.util.Stack;
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//1081:不同字符的最小子序列
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public class SmallestSubsequenceOfDistinctCharacters {
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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 SmallestSubsequenceOfDistinctCharacters().new Solution();
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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 smallestSubsequence(String s) {
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boolean[] isHave = new boolean[26];
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int[] count = new int[26];
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for (int i = 0; i < s.length(); i++) {
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count[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 (!isHave[ch - 'a']) {
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while (!stack.isEmpty() && stack.peek() > ch) {
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if (count[stack.peek() - 'a'] <= 0) {
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break;
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}
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isHave[stack.peek() - 'a'] = false;
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stack.pop();
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}
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isHave[ch - 'a'] = true;
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stack.push(ch);
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}
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count[ch - 'a']--;
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}
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StringBuilder str = new StringBuilder();
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while (!stack.isEmpty()) {
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str.insert(0, stack.pop());
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}
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return str.toString();
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//官网
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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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//
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// StringBuilder sb = new StringBuilder();
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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 (sb.length() > 0 && sb.charAt(sb.length() - 1) > ch) {
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// if (num[sb.charAt(sb.length() - 1) - 'a'] > 0) {
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// vis[sb.charAt(sb.length() - 1) - 'a'] = false;
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// sb.deleteCharAt(sb.length() - 1);
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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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// sb.append(ch);
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// }
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// num[ch - 'a']--;
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// }
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// return sb.toString();
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}
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}
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//leetcode submit region end(Prohibit modification and deletion)
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} |