Create take-k-of-each-character-from-left-and-right.cpp

Author: kamyu104

C++/take-k-of-each-character-from-left-and-right.cpp

@@ -0,0 +1,25 @@
+// Time:  O(n)
+// Space: O(1)
+
+// sliding window, two pointers
+class Solution {
+public:
+    int takeCharacters(string s, int k) {
+        vector<int> cnt(3);
+        for (const auto& c : s) {
+            ++cnt[c - 'a'];
+        }
+        if (*min_element(cbegin(cnt), cend(cnt)) < k) {
+            return -1;
+        }
+        int result = 0;
+        for (int right = 0, left = 0; right < size(s); ++right) {
+            --cnt[s[right] - 'a'];
+            while (cnt[s[right] - 'a'] < k) {
+                ++cnt[s[left++] - 'a'];
+            }
+            result = max(result, right - left + 1);
+        }
+        return size(s) - result;
+    }
+};