1051. Height Checker

//LEETCODE PROBLEM
//LEVEL - Easy
//1051. Height Checker


/* JAVA ACCEPTED SOLUTION - SORTING */
class Solution {
    public int heightChecker(int[] heights) {

        int []expected = new int[heights.length];

        for(int i=0;i<heights.length;i++){
            expected[i]=heights[i];
        }

        Arrays.sort(expected);

        int count=0;

        for(int i=0;i<heights.length;i++){
            if(heights[i] != expected[i]) count++;
        }

        return count;
        
    }
}

//TC - O(nlogn)

LOGIC- sort the array and then compare the both


/* JAVA ACCEPTED COUNTING SORT */
class Solution {
public int heightChecker(int[] heights) {
int[] count = new int[101];
for (int i = 0; i < heights.length; i++) {
count[heights[i]]++;
}
for (int i = 1; i < count.length; i++) {
count[i] += count[i-1];
}
int result = 0;
for (int i = heights.length-1; i >= 0; i--) {
count[heights[i]]--; // this is the correct location for heights[i] based on counting sort
if (heights[count[heights[i]]] != heights[i])
result++;
}
return result;
}
}




/* BUCKET SORTING */
class Solution {
    public int heightChecker(int[] heights) {         
        // perform a bucket-sort
        int[] bucket = new int[101];
        for(int number : heights) {
            bucket[number]++;
        }
        
        // check the ammount of disparities between the input array and the bucket
        int count = 0, index = 0;
        for(int i = 1; i <= 100; i++) {
            while(bucket[i] > 0) {
                if(i != heights[index++]) count++;
                bucket[i]--;
            }
        }
        return count;
    }