61 lines
1.7 KiB
Java
61 lines
1.7 KiB
Java
package com.zerroi.leetcode.ThreeFive;
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import java.util.Arrays;
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import java.util.HashMap;
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import java.util.Map;
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public class MajorityElement {
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public static void main(String[] args) {
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Solution solution = new Solution();
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int[] nums = new int[]{2, 2, 1, 1, 1, 2, 2};
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int res = solution.majorityElement(nums);
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// System.out.println("res = " + res);
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// System.out.println(5/2);
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}
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}
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/**
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* 给定一个大小为 n 的数组 nums ,返回其中的多数元素。多数元素是指在数组中出现次数 大于 ⌊ n/2 ⌋ 的元素。
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* 你可以假设数组是非空的,并且给定的数组总是存在多数元素。
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*/
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class Solution {
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public int majorityElement(int[] nums) {
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// 用HashMap key->元素 value->元素出现的次数
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Map<Integer, Integer> map = new HashMap<>();
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for (int num : nums) {
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if (map.containsKey(num)) {
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map.put(num, map.get(num) + 1);
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} else {
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map.put(num, 1);
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}
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}
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for (Integer key : map.keySet()) {
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if (map.get(key) > nums.length / 2) {
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return key;
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}
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}
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return 0;
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}
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public int majorityElementSort(int[] nums) {
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Arrays.sort(nums);
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return nums[nums.length / 2];
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}
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public int majorityElementVote(int[] nums) {
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int winner = nums[0];
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int count = 1;
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for (int i = 1; i < nums.length; i++) {
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if (nums[i] == winner) {
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count++;
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} else if (count == 0) {
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winner = nums[i];
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count++;
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} else {
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count--;
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}
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}
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return winner;
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}
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} |