feat(LeetCode): add solutions

LeetCode/first-bad-version.ts

@@ -0,0 +1,23 @@
+/**
+ * The knows API is defined in the parent class Relation.
+ * isBadVersion(version: number): boolean {
+ *     ...
+ * };
+ */
+
+var solution = function (isBadVersion: any) {
+  return function (n: number): number {
+    let l = 0, r = n;
+
+    while (l < r) {
+      let mid = Math.floor(l + (r - l) / 2);
+
+      if (isBadVersion(mid)) {
+        r = mid;
+      } else {
+        l = mid + 1;
+      }
+    }
+    return l;
+  };
+};

LeetCode/optimal-partition-of-string.ts

@@ -0,0 +1,36 @@
+// Solution 1
+function partitionString(s: string): number {
+  const lastSeen: number[] = new Array(26).fill(-1);
+
+  let count: number = 1;
+  let substrStart: number = 0;
+
+  for (let i = 0; i < s.length; i++) {
+    if (lastSeen[s.charCodeAt(i) - 'a'.charCodeAt(0)] >= substrStart) {
+      count++;
+      substrStart = i;
+    }
+    lastSeen[s.charCodeAt(i) - 'a'.charCodeAt(0)] = i;
+  }
+
+  return count;
+}
+
+// Solution 2
+function partitionString2(s: string): number {
+  let ans: number = 1;
+  const charSet: Set<string> = new Set();
+
+  for (const ch of s) {
+    if (!charSet.has(ch)) {
+      charSet.add(ch);
+      continue;
+    }
+
+    ans++;
+    charSet.clear();
+    charSet.add(ch);
+  }
+
+  return ans;
+}

LeetCode/search-insert-position.ts

@@ -0,0 +1,39 @@
+// Solution 1
+function searchInsert(nums: number[], target: number): number {
+  let l = 0;
+  let r = nums.length - 1;
+
+  while (l < r) {
+    let mid = Math.floor(l + (r - l) / 2);
+
+    if (nums[mid] === target) return mid;
+
+    if (nums[mid] < target) {
+      l = mid + 1;
+    } else {
+      r = mid - 1;
+    }
+  }
+
+  return nums[l] < target ? l + 1 : l;
+}
+
+// Solution 2
+function searchInsert2(nums: number[], target: number): number {
+  let l = 0;
+  let r = nums.length - 1;
+
+  while (l <= r) {
+    let mid = Math.floor(l + (r - l) / 2);
+
+    if (nums[mid] === target) return mid;
+
+    if (nums[mid] < target) {
+      l = mid + 1;
+    } else {
+      r = mid - 1;
+    }
+  }
+
+  return l;
+}

LeetCode/squares-of-a-sorted-array.ts

@@ -0,0 +1,5 @@
+function sortedSquares(nums: number[]): number[] {
+  return nums.map((x) => x * x).sort((a, b) => a - b);
+}
+
+// TODO: solve follow-up question