day 15

Author: sachuverma

Leetcode Daily Challenge/August-2021/15. Minimum Window Substring.cpp

@@ -0,0 +1,80 @@
+/*
+Minimum Window Substring
+========================
+
+Given two strings s and t of lengths m and n respectively, return the minimum window substring of s such that every character in t (including duplicates) is included in the window. If there is no such substring, return the empty string "".
+
+The testcases will be generated such that the answer is unique.
+
+A substring is a contiguous sequence of characters within the string.
+
+Example 1:
+Input: s = "ADOBECODEBANC", t = "ABC"
+Output: "BANC"
+Explanation: The minimum window substring "BANC" includes 'A', 'B', and 'C' from string t.
+
+Example 2:
+Input: s = "a", t = "a"
+Output: "a"
+Explanation: The entire string s is the minimum window.
+
+Example 3:
+Input: s = "a", t = "aa"
+Output: ""
+Explanation: Both 'a's from t must be included in the window.
+Since the largest window of s only has one 'a', return empty string.
+ 
+Constraints:
+m == s.length
+n == t.length
+1 <= m, n <= 105
+s and t consist of uppercase and lowercase English letters.
+ 
+Follow up: Could you find an algorithm that runs in O(m + n) time?
+*/
+
+class Solution
+{
+public:
+    bool same(unordered_map<char, int> &sMap, unordered_map<char, int> &tMap)
+    {
+        for (auto &i : tMap)
+        {
+            if (sMap[i.first] < i.second)
+                return false;
+        }
+        return true;
+    }
+
+    string minWindow(string s, string t)
+    {
+        int Size = s.size() + 1;
+        int i = 0, j = 0;
+        string ans, curr;
+
+        unordered_map<char, int> tMap, sMap;
+        for (auto &i : t)
+            tMap[i]++;
+
+        while (j < s.size())
+        {
+            sMap[s[j]]++;
+            j++;
+
+            while (same(sMap, tMap))
+            {
+                if (Size > j - i)
+                {
+                    Size = j - i;
+                    ans = "";
+                    for (int k = i; k < j; ++k)
+                        ans += s[k];
+                }
+                sMap[s[i]]--;
+                i++;
+            }
+        }
+
+        return ans;
+    }
+};

Leetcode Daily Challenge/August-2021/README.md

@@ -15,4 +15,6 @@
 | 10. | [Flip String to Monotone Increasing](https://leetcode.com/explore/challenge/card/august-leetcoding-challenge-2021/614/week-2-august-8th-august-14th/3876/)      |  [cpp](./10.%20Flip%20String%20to%20Monotone%20Increasing.cpp)  |
 | 11. | [Array of Doubled Pairs](https://leetcode.com/explore/challenge/card/august-leetcoding-challenge-2021/614/week-2-august-8th-august-14th/3877/)                  |         [cpp](./11.%20Array%20of%20Doubled%20Pairs.cpp)         |
 | 12. | [Group Anagrams](https://leetcode.com/explore/challenge/card/august-leetcoding-challenge-2021/614/week-2-august-8th-august-14th/3887/)                          |               [cpp](./12.%20Group%20Anagrams.cpp)               |
-| 13. | [Set Matrix Zeroes](https://leetcode.com/explore/challenge/card/august-leetcoding-challenge-2021/614/week-2-august-8th-august-14th/3888/)                          |               [cpp](./13.%20Set%20Matrix%20Zeroes.cpp)               |
+| 13. | [Set Matrix Zeroes](https://leetcode.com/explore/challenge/card/august-leetcoding-challenge-2021/614/week-2-august-8th-august-14th/3888/)                       |            [cpp](./13.%20Set%20Matrix%20Zeroes.cpp)             |
+| 15. | [Minimum Window Substring](https://leetcode.com/explore/challenge/card/august-leetcoding-challenge-2021/615/week-3-august-15th-august-21st/3891/)               |         [cpp](./15.%20Minimum%20Window%20Substring.cpp)         |
+| 16. | [Range Sum Query - Immutable](https://leetcode.com/explore/challenge/card/august-leetcoding-challenge-2021/615/week-3-august-15th-august-21st/3892/)            |     [cpp](./16.%20Range%20Sum%20Query%20-%20Immutable.cpp)      |