Today I have done Excel Sheet Column Number and leetcode's July LeetCoding Challenge with cpp.

Excel Sheet Column Number

Description

Given a string columnTitle that represents the column title as appear in an Excel sheet, return its corresponding column number.

For example:

A -> 1
B -> 2
C -> 3
...
Z -> 26
AA -> 27
AB -> 28 
...

Example 1:

Input: columnTitle = "A"
Output: 1

Example 2:

Input: columnTitle = "AB"
Output: 28

Example 3:

Input: columnTitle = "ZY"
Output: 701

Example 4:

Input: columnTitle = "FXSHRXW"
Output: 2147483647

Constraints:

• 1 <= columnTitle.length <= 7
• columnTitle consists only of uppercase English letters.
• columnTitle is in the range ["A", "FXSHRXW"].

Solution

class Solution {
public:
  int titleToNumber(string columnTitle) {
    int result = 0;
    for(auto c : columnTitle) {
      result *= 26;
      result += c - 'A' + 1;
    }
  }
};

July LeetCoding Challenge 14

Description

Custom Sort String

order and str are strings composed of lowercase letters. In order, no letter occurs more than once.

order was sorted in some custom order previously. We want to permute the characters of str so that they match the order that order was sorted. More specifically, if x occurs before y in order, then x should occur before y in the returned string.

Return any permutation of str (as a string) that satisfies this property.

Example:
Input: 
order = "cba"
str = "abcd"
Output: "cbad"
Explanation: 
"a", "b", "c" appear in order, so the order of "a", "b", "c" should be "c", "b", and "a". 
Since "d" does not appear in order, it can be at any position in the returned string. "dcba", "cdba", "cbda" are also valid outputs.

Note:

• order has length at most 26, and no character is repeated in order.
• str has length at most 200.
• order and str consist of lowercase letters only.

Solution

class Solution {
public:
  string customSortString(string order, string str) {
    int pos[128] = {};
    for(int i = 0; i < order.length(); ++i) pos[order[i]] = i + 1;
    sort(str.begin(), str.end(), [&](const char &a, const char &b) {
      return pos[a] < pos[b];
    });
    return str;
  }
};

class Solution {
public:
  string customSortString(string order, string str) {
    int cnt[128] = {};
    for(auto c : str) cnt[c] += 1;
    string answer;
    for(auto c : order) {
      while(cnt[c]) {
        answer.push_back(c);
        cnt[c] -= 1;
      }
    }
    for(char i = 'a'; i <= 'z'; ++i) {
      while(cnt[i]) {
        answer.push_back(i);
        cnt[i] -= 1;
      }
    }
    return answer;
  }
};