[khyo] Week 6

container-with-most-water/higeuni.js

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+/**
+ * @param {number[]} height
+ * @return {number}
+ * 
+ * complexity
+ * time: O(n)
+ * space: O(1)
+ */
+
+var maxArea = function(height) {
+  let answer = 0;
+  let l = 0, r = height.length - 1;
+
+  while(l < r) {
+      const area = (r - l) * Math.min(height[l], height[r]);
+
+      answer = area > answer ? area : answer;
+
+      if(height[l] < height[r]) {
+          l += 1;
+      }else {
+          r -= 1;
+      }
+  }
+
+  return answer;
+};
+

longest-increasing-subsequence/higeuni.js

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+/**
+ * @param {number[]} nums
+ * @return {number}
+ * 
+ * complexity
+ * time: O(nlogn) : lower_bound : O(logn), for문 : O(n)
+ * space: O(n)
+ */
+var lengthOfLIS = function(nums) {
+  const lower_bound = (arr, value) => {
+      let ret = -1;
+      let l = 0;
+      let r = arr.length - 1;
+
+      while(l <= r) {
+          const mid = Math.floor((l + r) / 2);
+          if(arr[mid] >= value) {
+              ret = mid;
+              r = mid - 1;
+          } else {
+              l = mid + 1;
+          }
+      }
+
+      return ret;
+  }
+
+  let sequence = [];
+
+  for(let i=0; i<nums.length; i++) {
+      const ret = lower_bound(sequence, nums[i])
+      if(ret === -1) {
+          sequence.push(nums[i]);
+      } else {
+          sequence[ret] = nums[i]
+      }
+  }
+
+  return sequence.length;
+};
+

valid-parentheses/higeuni.js

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+class Stack {
+  constructor() {
+      this.container = [];
+  }
+
+  push(item) {
+      this.container.push(item);
+  }
+
+  pop() {
+      return this.container.pop();
+  }
+
+  top() {
+      if (this.container.length === 0) return null;
+      return this.container[this.container.length - 1];
+  }
+
+  isEmpty() {
+      return this.container.length === 0;
+  }
+} 
+
+/**
+ * @param {string} s
+ * @return {boolean}
+ * 
+ * complexity
+ * time: O(n)
+ * space: O(n)
+ */
+var isValid = function(s) {
+    const stack = new Stack();
+    for (let x of s) {
+        if (x === '(' || x === '[' || x === '{') {
+            stack.push(x);
+        } else {
+            if (stack.isEmpty()) return false;
+            if (x === ')' && stack.top() !== '(') return false;
+            if (x === ']' && stack.top() !== '[') return false;
+            if (x === '}' && stack.top() !== '{') return false;
+            stack.pop();
+        }
+    }
+    return stack.isEmpty();
+};
+