add 3258

Author: fishercoder1534

paginated_contents/algorithms/4th_thousand/README.md

@@ -1,5 +1,6 @@
 | #    | Title                                                                                                                                                               | Solutions                                                                                                                         | Video                                                                         | Difficulty | Tag                                                                  
 |------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------|------------|----------------------------------------------------------------------
+| 3258 | [Count Substrings That Satisfy K-Constraint I](https://leetcode.com/problems/count-substrings-that-satisfy-k-constraint-i/)                                                                 | [Java](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/fourththousand/_3258.java) |                                                                               | Easy       |
 | 3254 | [Find the Power of K-Size Subarrays I](https://leetcode.com/problems/find-the-power-of-k-size-subarrays-i/)                                                                 | [Java](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/fourththousand/_3254.java) |                                                                               | Easy       |
 | 3249 | [Count the Number of Good Nodes](https://leetcode.com/problems/count-the-number-of-good-nodes/)                                                                 | [Java](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/fourththousand/_3249.java) |                                                                               | Medium     |
 | 3248 | [Snake in Matrix](https://leetcode.com/problems/snake-in-matrix/)                                                                 | [Java](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/fourththousand/_3248.java) |                                                                               | Easy       |

src/main/java/com/fishercoder/solutions/fourththousand/_3258.java

@@ -0,0 +1,31 @@
+package com.fishercoder.solutions.fourththousand;
+
+public class _3258 {
+    public static class Solution1 {
+        public int countKConstraintSubstrings(String s, int k) {
+            int ans = 0;
+            for (int i = 0; i < s.length(); i++) {
+                for (int j = i + 1; j <= s.length(); j++) {
+                    String candidate = s.substring(i, j);
+                    if (meetConstraints(candidate, k)) {
+                        ans++;
+                    }
+                }
+            }
+            return ans;
+        }
+
+        private boolean meetConstraints(String candidate, int k) {
+            int ones = 0;
+            int zeroes = 0;
+            for (char c : candidate.toCharArray()) {
+                if (c == '0') {
+                    zeroes++;
+                } else {
+                    ones++;
+                }
+            }
+            return ones <= k || zeroes <= k;
+        }
+    }
+}

src/test/java/com/fishercoder/fourththousand/_3258Test.java

@@ -0,0 +1,26 @@
+package com.fishercoder.fourththousand;
+
+import com.fishercoder.solutions.fourththousand._3258;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class _3258Test {
+    private _3258.Solution1 solution1;
+
+    @BeforeEach
+    public void setup() {
+        solution1 = new _3258.Solution1();
+    }
+
+    @Test
+    public void test1() {
+        assertEquals(12, solution1.countKConstraintSubstrings("10101", 1));
+    }
+
+    @Test
+    public void test2() {
+        assertEquals(25, solution1.countKConstraintSubstrings("1010101", 2));
+    }
+}