[Joo kangsan] 24.11.26 (#111)

* 56 / Merge Intervals / medium / 12m10s

* 139 / Word Break / medium / 27m50s

* 251 / Kth Largest Element in an Array / medium / 42m50s

* 235 / Lowest Common Ancestor of a Binary Search Tree / medium / 32m20s

* 1584 / Min Cost to Connect / medium

Author: JooKangsan

JooKangsan/10주차/139_Word_Break.js

@@ -0,0 +1,32 @@
+
+
+/**
+ * @param {string} s
+ * @param {string[]} wordDict
+ * @return {boolean}
+ */
+var wordBreak = function(s, wordDict) {
+    const memo = new Map();
+    
+    function dp(str, i = 0) {
+        if (str.length === 0) return true;
+        if (i >= wordDict.length) return false;
+ 
+        const key = str + ',' + i;
+        if (memo.has(key)) return memo.get(key);
+        
+        let word = wordDict[i];
+        if (str.slice(0, word.length) === word) {
+            if (dp(str.slice(word.length), 0)) {
+                memo.set(key, true);
+                return true;
+            }
+        }
+        
+        const result = dp(str, i + 1);
+        memo.set(key, result);
+        return result;
+    }
+    
+    return dp(s);
+};

JooKangsan/10주차/1584_Min_Cost_to_Connect_All_Points.js

@@ -0,0 +1,34 @@
+/**
+ * @param {number[][]} points
+ * @return {number}
+ */
+var minCostConnectPoints = function (points) {
+  const n = points.length;
+  const visited = new Array(n).fill(false);
+  const minDist = new Array(n).fill(Infinity);
+  minDist[0] = 0;
+  let result = 0;
+
+  for (let i = 0; i < n; i++) {
+    let x = -1;
+    for (let j = 0; j < n; j++) {
+      if (!visited[j] && (x === -1 || minDist[j] < minDist[x])) {
+        x = j;
+      }
+    }
+
+    visited[x] = true;
+    result += minDist[x];
+
+    for (let k = 0; k < n; k++) {
+      if (!visited[k]) {
+        const dist =
+          Math.abs(points[x][0] - points[k][0]) +
+          Math.abs(points[x][1] - points[k][1]);
+        minDist[k] = Math.min(minDist[k], dist);
+      }
+    }
+  }
+
+  return result;
+};

JooKangsan/10주차/215_Kth_Largest_Element_in_an_Array.js

@@ -0,0 +1,29 @@
+/**
+ * @param {number[]} nums
+ * @param {number} k
+ * @return {number}
+ */
+var findKthLargest = function(nums, k) {
+  let [min, max] = nums.reduce(([min, max], num) => 
+      [Math.min(min, num), Math.max(max, num)], 
+      [Infinity, -Infinity]
+  );
+  
+  const offset = min >= 0 ? 0 : -min;
+  const count = new Array(max + 1 + offset).fill(0);
+  
+  for(let num of nums) {
+      count[num + offset]++;
+  }
+  
+  let kthLargest;
+  for(let i = count.length - 1; i >= 0; i--) {
+      k -= count[i];
+      if(k <= 0) {
+          kthLargest = i - offset;
+          break;
+      }
+  }
+  
+  return kthLargest;
+};

JooKangsan/10주차/235_Lowest_Common_Ancestor_of_a_Binary_Search_Tree.js

@@ -0,0 +1,27 @@
+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val) {
+ *     this.val = val;
+ *     this.left = this.right = null;
+ * }
+ */
+
+/**
+ * @param {TreeNode} root
+ * @param {TreeNode} p
+ * @param {TreeNode} q
+ * @return {TreeNode}
+ */
+
+var lowestCommonAncestor = function(root, p, q) {
+  let min = Math.min(p.val, q.val)
+  let max = Math.max(p.val, q.val)
+
+  if(min > root.val) {
+      return lowestCommonAncestor(root.right, p, q)
+  } else if(max < root.val) {
+      return lowestCommonAncestor(root.left, p, q)
+  } else {
+      return root
+  }
+};

JooKangsan/10주차/56_Merge_Intervals.js

@@ -0,0 +1,18 @@
+/**
+ * @param {number[][]} intervals
+ * @return {number[][]}
+ */
+var merge = function (intervals) {
+  intervals.sort((a, b) => a[0] - b[0]);
+
+  for (let i = 1; i < intervals.length; i++) {
+    if (intervals[i][0] <= intervals[i - 1][1]) {
+      intervals[i][1] = Math.max(intervals[i][1], intervals[i - 1][1]);
+      intervals[i][0] = intervals[i - 1][0];
+      intervals.splice(i - 1, 1);
+      i--;
+    }
+  }
+
+  return intervals;
+};