1065

1065. Index Pairs of a String (Easy)

Given a string text and an array of strings words, return an array of all index pairs [i, j] so that the substring text[i...j] is in words.

Return the pairs [i, j] in sorted order (i.e., sort them by their first coordinate, and in case of ties sort them by their second coordinate).

 

Example 1:

Input: text = "thestoryofleetcodeandme", words = ["story","fleet","leetcode"]
Output: [[3,7],[9,13],[10,17]]

Example 2:

Input: text = "ababa", words = ["aba","ab"]
Output: [[0,1],[0,2],[2,3],[2,4]]
Explanation: Notice that matches can overlap, see "aba" is found in [0,2] and [2,4].

 

Constraints:

• 1 <= text.length <= 100
• 1 <= words.length <= 20
• 1 <= words[i].length <= 50
• text and words[i] consist of lowercase English letters.
• All the strings of words are unique.

Companies:
Amazon

Related Topics:
Array, String, Trie, Sorting

Solution 1.

// OJ: https://leetcode.com/problems/index-pairs-of-a-string/
// Author: github.com/lzl124631x
// Time: O((T-W) * (T+W) * N) where `T` is the length of `text`, `W` is the maximum length of word in `words`, and `N` is the length of `words`.
// Space: O(1) extra space
class Solution {
public:
    vector<vector<int>> indexPairs(string text, vector<string>& A) {
        vector<vector<int>> ans;
        for (auto &s : A) {
            int i = text.find(s);
            while (i != string::npos) {
                ans.push_back({ i, i + (int)s.size() - 1 });
                i = text.find(s, i + 1);
            }
        }
        sort(begin(ans), end(ans));
        return ans;
    }
};