Today I have done Add to Array-Form of Integer and leetcode's March LeetCoding Challenge with cpp.

Add to Array-Form of Integer

Description

For a non-negative integer X, the array-form of X is an array of its digits in left to right order. For example, if X = 1231, then the array form is [1,2,3,1].

Given the array-form A of a non-negative integer X, return the array-form of the integer X+K.

Example 1:

Input: A = [1,2,0,0], K = 34
Output: [1,2,3,4]
Explanation: 1200 + 34 = 1234

Example 2:

Input: A = [2,7,4], K = 181
Output: [4,5,5]
Explanation: 274 + 181 = 455

Example 3:

Input: A = [2,1,5], K = 806
Output: [1,0,2,1]
Explanation: 215 + 806 = 1021

Example 4:

Input: A = [9,9,9,9,9,9,9,9,9,9], K = 1
Output: [1,0,0,0,0,0,0,0,0,0,0]
Explanation: 9999999999 + 1 = 10000000000

Note：

1. 1 <= A.length <= 10000
2. 0 <= A[i] <= 9
3. 0 <= K <= 10000
4. If A.length > 1, then A[0] != 0

Solution

class Solution {
public:
    vector<int> addToArrayForm(vector<int>& A, int K) {
        reverse(A.begin(), A.end());
        int carry = 0;
        int pos = 0;
        int len = A.size();
        while(carry || K) {
            int result = carry + K % 10;
            if(pos < len) result += A[pos];
            carry = result / 10;
            if(pos < len) A[pos] = result % 10;
            else A.push_back(result % 10);
            K /= 10;
            pos += 1;
        }
        reverse(A.begin(), A.end());
        return move(A);
    }
};

March LeetCoding Challenge 8

Description

Remove Palindromic Subsequences

Given a string s consisting only of letters 'a' and 'b'. In a single step you can remove one palindromic subsequence from s.

Return the minimum number of steps to make the given string empty.

A string is a subsequence of a given string, if it is generated by deleting some characters of a given string without changing its order.

A string is called palindrome if is one that reads the same backward as well as forward.

Example 1:

Input: s = "ababa"
Output: 1
Explanation: String is already palindrome

Example 2:

Input: s = "abb"
Output: 2
Explanation: "abb" -> "bb" -> "". 
Remove palindromic subsequence "a" then "bb".

Example 3:

Input: s = "baabb"
Output: 2
Explanation: "baabb" -> "b" -> "". 
Remove palindromic subsequence "baab" then "b".

Example 4:

Input: s = ""
Output: 0

Constraints:

• 0 <= s.length <= 1000
• s only consists of letters 'a' and 'b'

Solution

class Solution {
    bool isPalindrome(string &s) {
        int len = s.length();
        for(int i = 0; i * 2 < len; ++i) {
            if(s[i] != s[len - 1 - i]) return false;
        }
        return true;
    }
public:
    int removePalindromeSub(string s) {
        if(s.length() == 0) return 0;
        if(isPalindrome(s)) return 1;
        return 2;
    }
};