[Sehwan] Week12 solution with JavaScript (#192)

* Added solutions

* Added jump game solution

Author: nhistory

jump-game/nhistory.js

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+var canJump = function (nums) {
+  let pointer = 0;
+  for (let i = 0; i < nums.length; i++) {
+    if (i > pointer) return false;
+    pointer = Math.max(pointer, i + nums[i]);
+    if (pointer >= nums.length - 1) return true;
+  }
+  return false;
+};
+
+// TC: O(n)
+// SC: O(1)

longest-common-subsequence/nhistory.js

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+var longestCommonSubsequence = function (text1, text2) {
+  // Edge case
+  if (text1.length === 1 && text2.length === 1 && text1 === text2) return 1;
+
+  let dp = Array.from({ length: text1.length + 1 }, () =>
+    Array(text2.length + 1).fill(0)
+  );
+
+  for (let i = 1; i <= text1.length; i++) {
+    for (let j = 1; j <= text2.length; j++) {
+      if (text1[i - 1] === text2[j - 1]) {
+        dp[i][j] = dp[i - 1][j - 1] + 1;
+      } else {
+        dp[i][j] = Math.max(dp[i - 1][j], dp[i][j - 1]);
+      }
+    }
+  }
+
+  return dp[text1.length][text2.length];
+};
+
+// m = text1.length | n = text2.length
+// TC: O(m*n)
+// SC: O(m*n)

longest-increasing-subsequence/nhistory.js

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+var lengthOfLIS = function (nums) {
+  if (nums.length === 1) return 1;
+  let dp = new Array(nums.length).fill(1);
+
+  for (let i = 0; i < nums.length; i++) {
+    for (let j = 0; j < i; j++) {
+      if (nums[i] > nums[j]) {
+        dp[i] = Math.max(dp[i], dp[j] + 1);
+      }
+    }
+  }
+  return Math.max(...dp);
+};
+
+// TC: O(n^2)
+// SC: O(n)

maximum-subarray/nhistory.js

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+var maxSubArray = function (nums) {
+  // Edge case
+  if (nums.length === 1) return nums[0];
+
+  let maxSum = nums[0];
+  let curSum = nums[0];
+
+  for (let i = 1; i < nums.length; i++) {
+    curSum = Math.max(nums[i], curSum + nums[i]);
+    maxSum = Math.max(maxSum, curSum);
+  }
+
+  return maxSum;
+};
+
+// TC: O(n)
+// SC: O(1)

unique-paths/nhistory.js

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+var uniquePaths = function (m, n) {
+  // Edge case
+  if (m === 1 || n === 1) return 1;
+
+  let rowArr = new Array(n).fill(1);
+
+  for (let row = 1; row < m; row++) {
+    for (let col = 1; col < n; col++) {
+      rowArr[col] += rowArr[col - 1];
+    }
+  }
+  return rowArr[n - 1];
+};
+
+// TC: O(m*n)
+// SC: O(n)