2515. Shortest Distance to Target String in a Circular Array

You are given a 0-indexed circular string array words and a string target. A circular array means that the array’s end connects to the array’s beginning.

• Formally, the next element of words[i] is words[(i + 1) % n] and the previous element of words[i] is words[(i - 1 + n) % n], where n is the length of words.

Starting from startIndex, you can move to either the next word or the previous word with 1 step at a time.

Return the shortest distance needed to reach the string target. If the string target does not exist in words, return -1.

class Solution {
public:
    int closetTarget(vector<string>& words, string target, int startIndex) {
        bool has = false;
        for(auto w : words) {
            if(w == target) has = true;
        }
        if(!has) return -1;
        int res = 0;
        int l = startIndex, r = startIndex;
        while(words[l] != target and words[r] != target) {
            res += 1;
            l = (l - 1 + words.size()) % words.size();
            r = (r + 1) % words.size();
        }
        return res;
    }
};