[Oracle] LeetCode 848. Shifting Letters

You are given a string s of lowercase English letters and an integer array shifts of the same length.

Call the shift() of a letter, the next letter in the alphabet, (wrapping around so that 'z' becomes 'a').

For example, shift('a') = 'b', shift('t') = 'u', and shift('z') = 'a'.
Now for each shifts[i] = x, we want to shift the first i + 1 letters of s, x times.

Return the final string after all such shifts to s are applied.

Solution

使用后缀数组即可。对于第 \(i\) 个位置的字符，偏移之后则为：

class Solution {
private:
    string ans="";
    long long pref[100002];
    
public:
    string shiftingLetters(string s, vector<int>& shifts) {
        int n = shifts.size();
        
        for(int i=n-1;i>=0;i--){
            pref[i] = shifts[i]+pref[i+1];
        }
        for(int i=0;i<n;i++){
            ans+= (char)('a'+ (s[i]-'a'+pref[i])%26);
        }
        return ans;
    }
};