LeetCode-821. Shortest Distance to a Character

Given a string ​​S​​​ and a character ​​C​​​, return an array of integers representing the shortest distance from the character ​​C​​ in the string.

Example 1:

Input: S = "loveleetcode", C = 'e'
Output: [3, 2, 1, 0, 1, 0, 0, 1, 2, 2, 1, 0]

Note:

1. ​​S​​​ string length is in​​[1, 10000].​​
2. ​​C​​​ is a single character, and guaranteed to be in string​​S​​.
3. All letters in​​S​​​ and​​C​​ are lowercase.

题解：

class Solution {
public:
  vector<int> shortestToChar(string S, char C) {
    vector<int> ans;
    for (int i = 0; i < S.length(); i++) {
      if (S[i] == C) {
        ans.push_back(0);
        continue;
      }
      int j, k;
      bool front = false, back = false;
      for (j = i - 1; j >= 0; j--) {
        if (S[j] == C) {
          back = true;
          break;
        }
      }
      for (k = i + 1; k < S.size(); k++) {
        if (S[k] == C) {
          front = true;
          break;
        }
      }
      if (front == true && back ==false) {
        ans.push_back(k - i);
      }
      else if (front == false && back == true) {
        ans.push_back(i - j);
      }
      else if (front == true && back == true) {
        ans.push_back(min(k - i, i - j));
      }
    }
    return ans;
  }
};