题目
Given an array of integers and an integer k, find out whether there are two distinct indices i and j in the array such that nums[i] = nums[j] and the absolute difference between i and j is at most k.
Example 1:
Input: nums = [1,2,3,1], k = 3
Output: true
Example 2:
Input: nums = [1,0,1,1], k = 1
Output: true
Example 3:
Input: nums = [1,2,3,1,2,3], k = 2
Output: false
解析
题目的意思其实就是在k的长度范围内,寻找是不是有相同的两个元素。因此需要遍历整个数组,每个都进行对比,其运行的次数为:
(n - 1) + (n - 2) + ... + 1 = n(n-1)/2
时间复杂度为O(n2)。
代码(C语言)
bool containsNearbyDuplicate(int* nums, int numsSize, int k) {
if (nums == NULL || numsSize == 0)
return false;
for (int i = 0; i < numsSize - 1; ++i) {
for (int j = i + 1; j < numsSize; ++j) {
if (nums[i] == nums[j]) {
if (j - i <= k)
return true;
}
}
}
return false;
}