[mintheon] Week2

3sum/mintheon.java

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+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+class Solution {
+  public List<List<Integer>> threeSum(int[] nums) {
+    Arrays.sort(nums);
+
+    Set<List<Integer>> answer = new HashSet<>();
+
+    for(int i = 0; i < nums.length - 2; i++) {
+      int left = i + 1;
+      int right = nums.length - 1;
+
+      while(left < right) {
+        int sum = nums[i] + nums[left] + nums[right];
+
+        if(sum < 0) {
+          left++;
+        } else if(sum > 0) {
+          right--;
+        } else{
+          answer.add(List.of(nums[i], nums[left], nums[right]));
+
+          left++;
+          right--;
+        }
+      }
+    }
+
+    return new ArrayList<>(answer);
+  }
+}

climbing-stairs/mintheon.java

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+class Solution {
+  public int climbStairs(int n) {
+    int[] stepCount = new int[n + 1];
+
+    if(n == 1) {
+      return 1;
+    }
+
+    stepCount[1] = 1;
+    stepCount[2] = 2;
+    for(int i = 3; i <= n; i++) {
+      stepCount[i] = stepCount[i - 1] + stepCount[i - 2];
+    }
+
+    return stepCount[n];
+  }
+}

valid-anagram/mintheon.java

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+import java.util.Arrays;
+
+class Solution {
+  public boolean isAnagram(String s, String t) {
+    char[] sChar = s.toCharArray();
+    char[] tChar = t.toCharArray();
+
+    Arrays.sort(sChar);
+    Arrays.sort(tChar);
+
+    return Arrays.equals(sChar, tChar);
+  }
+}