Problem
Given the array nums, for each nums[i] find out how many numbers in the array are smaller than it. That is, for each nums[i] you have to count the number of valid j's such that j != i and nums[j] < nums[i].
Return the answer in an array.
Example 1:
Input: nums = [8,1,2,2,3]
Output: [4,0,1,1,3]
Explanation:
For nums[0]=8 there exist four smaller numbers than it (1, 2, 2 and 3).
For nums[1]=1 does not exist any smaller number than it.
For nums[2]=2 there exist one smaller number than it (1).
For nums[3]=2 there exist one smaller number than it (1).
For nums[4]=3 there exist three smaller numbers than it (1, 2 and 2).
Example 2:
Input: nums = [6,5,4,8]
Output: [2,1,0,3]
Example 3:
Input: nums = [7,7,7,7]
Output: [0,0,0,0]
Constraints:
2 <= nums.length <= 5000 <= nums[i] <= 100
Solution (Java)
class Solution {
public int[] smallerNumbersThanCurrent(int[] nums) {
int[] ans = new int[nums.length];
int[] temp = new int[101];
for (int num : nums) {
temp[num]++;
}
for (int i = 1; i < 101; i++) {
temp[i] += temp[i - 1];
}
for (int i = 0; i < ans.length; i++) {
if (nums[i] == 0) {
ans[i] = 0;
} else {
ans[i] = temp[nums[i] - 1];
}
}
return ans;
}
}
Explain:
nope.
Complexity:
- Time complexity : O(n).
- Space complexity : O(n).