README_EN.md

comments	difficulty	edit_url	rating	source	tags
true	Easy	https://github.com/doocs/leetcode/edit/main/solution/1300-1399/1331.Rank%20Transform%20of%20an%20Array/README_EN.md	1355	Biweekly Contest 18 Q1	Array Hash Table Sorting

1331. Rank Transform of an Array

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Description

Given an array of integers arr, replace each element with its rank.

The rank represents how large the element is. The rank has the following rules:

• Rank is an integer starting from 1.
• The larger the element, the larger the rank. If two elements are equal, their rank must be the same.
• Rank should be as small as possible.

 

Example 1:

Input: arr = [40,10,20,30]
Output: [4,1,2,3]
Explanation: 40 is the largest element. 10 is the smallest. 20 is the second smallest. 30 is the third smallest.

Example 2:

Input: arr = [100,100,100]
Output: [1,1,1]
Explanation: Same elements share the same rank.

Example 3:

Input: arr = [37,12,28,9,100,56,80,5,12]
Output: [5,3,4,2,8,6,7,1,3]

 

Constraints:

• 0 <= arr.length <= 105
• -109 <= arr[i] <= 109

Solutions

Solution 1

Python3

class Solution:
    def arrayRankTransform(self, arr: List[int]) -> List[int]:
        t = sorted(set(arr))
        return [bisect_right(t, x) for x in arr]

Java

class Solution {
    public int[] arrayRankTransform(int[] arr) {
        int n = arr.length;
        int[] t = arr.clone();
        Arrays.sort(t);
        int m = 0;
        for (int i = 0; i < n; ++i) {
            if (i == 0 || t[i] != t[i - 1]) {
                t[m++] = t[i];
            }
        }
        int[] ans = new int[n];
        for (int i = 0; i < n; ++i) {
            ans[i] = Arrays.binarySearch(t, 0, m, arr[i]) + 1;
        }
        return ans;
    }
}

C++

class Solution {
public:
    vector<int> arrayRankTransform(vector<int>& arr) {
        vector<int> t = arr;
        sort(t.begin(), t.end());
        t.erase(unique(t.begin(), t.end()), t.end());
        vector<int> ans;
        for (int x : arr) {
            ans.push_back(upper_bound(t.begin(), t.end(), x) - t.begin());
        }
        return ans;
    }
};

Go

func arrayRankTransform(arr []int) (ans []int) {
	t := make([]int, len(arr))
	copy(t, arr)
	sort.Ints(t)
	m := 0
	for i, x := range t {
		if i == 0 || x != t[i-1] {
			t[m] = x
			m++
		}
	}
	t = t[:m]
	for _, x := range arr {
		ans = append(ans, sort.SearchInts(t, x)+1)
	}
	return
}

TypeScript

function arrayRankTransform(arr: number[]): number[] {
    const t = [...arr].sort((a, b) => a - b);
    let m = 0;
    for (let i = 0; i < t.length; ++i) {
        if (i === 0 || t[i] !== t[i - 1]) {
            t[m++] = t[i];
        }
    }
    const search = (t: number[], right: number, x: number) => {
        let left = 0;
        while (left < right) {
            const mid = (left + right) >> 1;
            if (t[mid] > x) {
                right = mid;
            } else {
                left = mid + 1;
            }
        }
        return left;
    };
    const ans: number[] = [];
    for (const x of arr) {
        ans.push(search(t, m, x));
    }
    return ans;
}