[Jeehay28] WEEK 06

container-with-most-water/Jeehay28.js

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+/**
+ * @param {number[]} height
+ * @return {number}
+ */
+
+// Time Complexity: O(n)
+// Space Complexity: O(1)
+var maxArea = function (height) {
+  let start = 0;
+  let end = height.length - 1;
+  let maxArea = 0;
+
+  while (start < end) {
+    const area = (end - start) * Math.min(height[start], height[end]);
+    maxArea = Math.max(area, maxArea);
+
+    // The shorter height limits the area.
+    // By moving the pointer associated with the shorter height,
+    // the algorithm maximizes the chance of finding a taller line that can increase the area.
+    // This is the essence of the two-pointer strategy for the container problem.
+    if (height[start] < height[end]) {
+      start += 1;
+    } else {
+      end -= 1;
+    }
+  }
+  return maxArea;
+};
+

valid-parentheses/Jeehay28.js

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+/**
+ * @param {string} s
+ * @return {boolean}
+ */
+
+// Time Complexity: O(n)
+// Space Complexity: O(n)
+var isValid = function (s) {
+  const obj = {
+    "(" : ")",
+    "{" : "}",
+    "[" : "]",
+  };
+
+  let stack = [];
+
+  for (any of s) {
+    // open bracket
+    if (obj[any]) {
+      stack.push(any);
+    } else {
+      // close bracket
+      if (stack.length === 0) {
+        return false;
+      } else if (obj[stack[stack.length - 1]] !== any) {
+        return false;
+      } else {
+        stack.pop();
+      }
+    }
+  }
+  return stack.length === 0 ? true : false;
+};
+
+