Week6 Solutions ver1

Author: hoyeongkwak

container-with-most-water/hoyeongkwak.java

@@ -0,0 +1,22 @@
+/*
+Time Complexity : O(n)
+Space Complexity : O(1)
+*/
+class Solution {
+    public int maxArea(int[] height) {
+        int left = 0;
+        int right = height.length - 1;
+        int area = 0;
+
+        while (left < right) {
+            int currentArea = (right - left) * Math.min(height[left], height[right]);
+            area = Math.max(area, currentArea);
+            if (height[left] < height[right]) {
+                left++;
+            } else {
+                right--;
+            }
+        }
+        return area;
+    }
+}

valid-parentheses/hoyeongkwak.java

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+class Solution {
+    public boolean isValid(String s) {
+        if (s == null || s.length() % 2 != 0) {
+            return false;
+        }
+        Stack<Character> stack = new Stack<>();
+        HashMap<Character, Character> strList = new HashMap<>();
+        strList.put(')', '(');
+        strList.put(']', '[');
+        strList.put('}', '{');
+
+        for (char c : s.toCharArray()) {
+            if (strList.containsKey(c)) { 
+                if (stack.isEmpty() || stack.pop() != strList.get(c)) {
+                    return false;
+                }
+            } else {
+                stack.push(c);
+            }
+        }
+        
+        return stack.isEmpty();
+    }
+}