README_EN.md

1781. Sum of Beauty of All Substrings

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Description

The beauty of a string is the difference in frequencies between the most frequent and least frequent characters.

• For example, the beauty of "abaacc" is 3 - 1 = 2.

Given a string s, return the sum of beauty of all of its substrings.

 

Example 1:

Input: s = "aabcb"
Output: 5
Explanation: The substrings with non-zero beauty are ["aab","aabc","aabcb","abcb","bcb"], each with beauty equal to 1.

Example 2:

Input: s = "aabcbaa"
Output: 17

 

Constraints:

• 1 <= s.length <= 500
• s consists of only lowercase English letters.

Solutions

Python3

class Solution:
    def beautySum(self, s: str) -> int:
        ans, n = 0, len(s)
        for i in range(n):
            cnt = Counter()
            for j in range(i, n):
                cnt[s[j]] += 1
                ans += max(cnt.values()) - min(cnt.values())
        return ans

Java

class Solution {
    public int beautySum(String s) {
        int ans = 0;
        int n = s.length();
        for (int i = 0; i < n; ++i) {
            int[] cnt = new int[26];
            for (int j = i; j < n; ++j) {
                ++cnt[s.charAt(j) - 'a'];
                int mi = 1000, mx = 0;
                for (int v : cnt) {
                    if (v > 0) {
                        mi = Math.min(mi, v);
                        mx = Math.max(mx, v);
                    }
                }
                ans += mx - mi;
            }
        }
        return ans;
    }
}

C++

class Solution {
public:
    int beautySum(string s) {
        int ans = 0;
        int n = s.size();
        int cnt[26];
        for (int i = 0; i < n; ++i) {
            memset(cnt, 0, sizeof cnt);
            for (int j = i; j < n; ++j) {
                ++cnt[s[j] - 'a'];
                int mi = 1000, mx = 0;
                for (int& v : cnt) {
                    if (v > 0) {
                        mi = min(mi, v);
                        mx = max(mx, v);
                    }
                }
                ans += mx - mi;
            }
        }
        return ans;
    }
};

Go

func beautySum(s string) (ans int) {
	for i := range s {
		cnt := [26]int{}
		for j := i; j < len(s); j++ {
			cnt[s[j]-'a']++
			mi, mx := 1000, 0
			for _, v := range cnt {
				if v > 0 {
					if mi > v {
						mi = v
					}
					if mx < v {
						mx = v
					}
				}
			}
			ans += mx - mi
		}
	}
	return
}

JavaScript

/**
 * @param {string} s
 * @return {number}
 */
var beautySum = function (s) {
    let ans = 0;
    for (let i = 0; i < s.length; ++i) {
        const cnt = new Map();
        for (let j = i; j < s.length; ++j) {
            cnt.set(s[j], (cnt.get(s[j]) || 0) + 1);
            const t = Array.from(cnt.values());
            ans += Math.max(...t) - Math.min(...t);
        }
    }
    return ans;
};

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