1405. Longest Happy String

A string is called happy if it does not have any of the strings 'aaa', 'bbb' or 'ccc' as a substring.

Given three integers a, b and c, return any string s, which satisfies following conditions:

• s is happy and longest possible.
• s contains at most a occurrences of the letter 'a', at most b occurrences of the letter 'b' and at most c occurrences of the letter 'c'.
• s will only contain 'a', 'b' and 'c' letters.

If there is no such string s return the empty string "".

Example 1:

Input: a = 1, b = 1, c = 7
Output: "ccaccbcc"
Explanation: "ccbccacc" would also be a correct answer.

Example 2:

Input: a = 2, b = 2, c = 1
Output: "aabbc"

Example 3:

Input: a = 7, b = 1, c = 0
Output: "aabaa"
Explanation: It's the only correct answer in this case.

Constraints:

• 0 <= a, b, c <= 100
• a + b + c > 0

class Solution {
    String generate(int a, int b, int c, String aa, String bb, String cc) {
        if (a < b)
            return generate(b, a, c, bb, aa, cc);
        if (b < c)
            return generate(a, c, b, aa, cc, bb);
        if (b == 0)
            return aa.repeat(Math.min(2, a));
        int use_a = Math.min(2, a), use_b = a - use_a >= b ? 1 : 0; 
        return aa.repeat(use_a) + bb.repeat(use_b) +
            generate(a - use_a, b - use_b, c, aa, bb, cc);    
    }
    public String longestDiverseString(int a, int b, int c) {
        return generate(a, b, c, "a", "b", "c");
    }
}

屌。。https://leetcode.com/problems/longest-happy-string/discuss/564277/C%2B%2BJava-a-greater-b-greater-c

class Solution {
    public String longestDiverseString(int a, int b, int c) {
        StringBuilder sb = new StringBuilder();
        int size = a + b + c;
        int A = 0, B = 0, C = 0;
        for(int i = 0; i < size; i++) {
            if ((a >= b && a >= c && A != 2) || (B == 2 && a > 0) || (C == 2 && a > 0))  {
                sb.append("a");
                a--;
                A++;
                B = 0;
                C = 0;  
            } else if ((b >= a && b >= c && B != 2) || (A == 2 && b > 0) || (C == 2 && b > 0)) {
                sb.append("b");
                b--;
                B++;
                A = 0;
                C = 0;
            } else if ((c >= a && c >= b && C != 2) || (B == 2 && c > 0) || (A == 2 && c > 0)) {
                sb.append("c");
                c--;
                C++;
                A = 0;
                B = 0;  
            }
        }
        return sb.toString();
    }
}

屌。。。https://leetcode.com/problems/longest-happy-string/discuss/564273/Java-Happy-Greedy-String-without-PQ