剑指 Offer 03. 数组中重复的数字(哈希表或排序)

题目

哈希表 8ms

class Solution {
    
    
    public int findRepeatNumber(int[] nums) {
    
    
        HashSet<Integer> set = new HashSet<>();
        for (int i = 0; i < nums.length; i++) {
    
    
            if (set.contains(nums[i])) return nums[i];
            set.add(nums[i]);
        }
        return 0;
    }
}

排序 3ms

   public int findRepeatNumber(int[] nums) {
    
    
        Arrays.sort(nums);
        for (int i = 0; i < nums.length -1; i++) {
    
    
            if (nums[i] == nums[i+1]) return nums[i];
        }
        return 0;
    }