feat(curriculum): daily challenges 197-212 (freeCodeCamp#65864)

Co-authored-by: majestic-owl448 <26656284+majestic-owl448@users.noreply.github.com>

Author: moT01

curriculum/challenges/english/blocks/daily-coding-challenges-javascript/697a49e9860d24853adef67c.md

@@ -12,7 +12,7 @@ Given an array representing the weights of the athletes on a bobsled team and a
 - The length of the array determines the team size: 1, 2 or 4 person teams.
 - All given weight values are in kilograms (kg).
 
-The bobsled (sled by iteself) must have a minimum weight of:
+The bobsled (sled by itself) must have a minimum weight of:
 
 - 162 kg for a 1-person team
 - 170 kg for a 2-person team

curriculum/challenges/english/blocks/daily-coding-challenges-javascript/698a1a73ade5ac0e19180fa0.md

@@ -0,0 +1,129 @@
+---
+id: 698a1a73ade5ac0e19180fa0
+title: "Challenge 197: Blood Type Compatibility"
+challengeType: 28
+dashedName: challenge-197
+---
+
+# --description--
+
+Given a donor blood type and a recipient blood type, determine whether the donor can give blood to the recipient.
+
+Each blood type consists of:
+
+- A letter: `"A"`, `"B"`, `"AB"`, or `"O"`
+- And an Rh factor: `"+"` or `"-"`
+
+Blood types will be one of the valid letters followed by an Rh factor. For example, `"AB+"` and `"O-"` are valid blood types.
+
+Letter Rules:
+
+- `"O"` can donate to other letter type.
+- `"A"` can donate to `"A"` and `"AB"`.
+- `"B"` can donate to `"B"` and `"AB"`.
+- `"AB"` can donate only to `"AB"`.
+
+Rh Rules:
+
+- Negative (`"-"`) can donate to both `"-"` and `"+"`.
+- Positive (`"+"`) can donate only to `"+"`.
+
+Both letter and Rh rule must pass for a donor to be able to donate to the recipient.
+
+# --hints--
+
+`canDonate("B+", "B+")` should return `true`.
+
+```js
+assert.isTrue(canDonate("B+", "B+"));
+```
+
+`canDonate("O-", "AB-")` should return `true`.
+
+```js
+assert.isTrue(canDonate("O-", "AB-"));
+```
+
+`canDonate("O+", "A-")` should return `false`.
+
+```js
+assert.isFalse(canDonate("O+", "A-"));
+```
+
+`canDonate("A+", "AB+")` should return `true`.
+
+```js
+assert.isTrue(canDonate("A+", "AB+"));
+```
+
+`canDonate("A-", "B-")` should return `false`.
+
+```js
+assert.isFalse(canDonate("A-", "B-"));
+```
+
+`canDonate("B-", "AB+")` should return `true`.
+
+```js
+assert.isTrue(canDonate("B-", "AB+"));
+```
+
+`canDonate("B-", "A+")` should return `false`.
+
+```js
+assert.isFalse(canDonate("B-", "A+"));
+```
+
+`canDonate("O-", "O+")` should return `true`.
+
+```js
+assert.isTrue(canDonate("O-", "O+"));
+```
+
+`canDonate("O+", "O-")` should return `false`.
+
+```js
+assert.isFalse(canDonate("O+", "O-"));
+```
+
+`canDonate("AB+", "AB-")` should return `false`.
+
+```js
+assert.isFalse(canDonate("AB+", "AB-"));
+```
+
+# --seed--
+
+## --seed-contents--
+
+```js
+function canDonate(donor, recipient) {
+
+  return donor;
+}
+```
+
+# --solutions--
+
+```js
+function canDonate(donor, recipient) {
+  const donorType = donor.slice(0, -1);
+  const donorRh = donor.slice(-1);
+
+  const recipientType = recipient.slice(0, -1);
+  const recipientRh = recipient.slice(-1);
+
+  const aboCompatibility = {
+    "O": ["A", "B", "AB", "O"],
+    "A": ["A", "AB"],
+    "B": ["B", "AB"],
+    "AB": ["AB"]
+  };
+
+  const aboMatch = aboCompatibility[donorType].includes(recipientType);
+  const rhMatch =
+    donorRh === "-" || (donorRh === "+" && recipientRh === "+");
+
+  return aboMatch && rhMatch;
+}
+```

curriculum/challenges/english/blocks/daily-coding-challenges-javascript/698a1a73ade5ac0e19180fa1.md

@@ -0,0 +1,78 @@
+---
+id: 698a1a73ade5ac0e19180fa1
+title: "Challenge 198: Business Day Count"
+challengeType: 28
+dashedName: challenge-198
+---
+
+# --description--
+
+Given a start date and an end date, return the number of business days between the two.
+
+- Given dates are in the format `"YYYY-MM-DD"`.
+- Weekdays are business days (Monday through Friday).
+- Weekends are not business days (Saturday and Sunday).
+- Include both the start and end dates when counting.
+
+# --hints--
+
+`countBusinessDays("2026-02-24", "2026-02-26")` should return `3`.
+
+```js
+assert.equal(countBusinessDays("2026-02-24", "2026-02-26"), 3);
+```
+
+`countBusinessDays("2026-02-24", "2026-02-28")` should return `4`.
+
+```js
+assert.equal(countBusinessDays("2026-02-24", "2026-02-28"), 4);
+```
+
+`countBusinessDays("2026-02-21", "2026-03-01")` should return `5`.
+
+```js
+assert.equal(countBusinessDays("2026-02-21", "2026-03-01"), 5);
+```
+
+`countBusinessDays("2026-03-08", "2026-03-17")` should return `7`.
+
+```js
+assert.equal(countBusinessDays("2026-03-08", "2026-03-17"), 7);
+```
+
+`countBusinessDays("2026-02-24", "2027-02-24")` should return `262`.
+
+```js
+assert.equal(countBusinessDays("2026-02-24", "2027-02-24"), 262);
+```
+
+# --seed--
+
+## --seed-contents--
+
+```js
+function countBusinessDays(start, end) {
+
+  return start;
+}
+```
+
+# --solutions--
+
+```js
+function countBusinessDays(start, end) {
+  const startDate = new Date(start + "T00:00:00Z");
+  const endDate = new Date(end + "T00:00:00Z");
+
+  let count = 0;
+  let current = new Date(startDate);
+
+  while (current <= endDate) {
+    const day = current.getUTCDay();
+    if (day !== 0 && day !== 6) count++;
+    current.setUTCDate(current.getUTCDate() + 1);
+  }
+
+  return count;
+}
+```

curriculum/challenges/english/blocks/daily-coding-challenges-javascript/698a1a73ade5ac0e19180fa2.md

@@ -0,0 +1,71 @@
+---
+id: 698a1a73ade5ac0e19180fa2
+title: "Challenge 199: Sequential Difference"
+challengeType: 28
+dashedName: challenge-199
+---
+
+# --description--
+
+Given an array of numbers, return a new array containing the value needed to get from each number to the next number.
+
+- For the last number, use `0` since there is no next number.
+
+For example, given `[1, 2, 4, 7]`, return `[1, 2, 3, 0]`.
+
+# --hints--
+
+`findDifferences([1, 2, 4, 7])` should return `[1, 2, 3, 0]`.
+
+```js
+assert.deepEqual(findDifferences([1, 2, 4, 7]), [1, 2, 3, 0]);
+```
+
+`findDifferences([10, 15, 19, 22, 24, 25])` should return `[5, 4, 3, 2, 1, 0]`.
+
+```js
+assert.deepEqual(findDifferences([10, 15, 19, 22, 24, 25]), [5, 4, 3, 2, 1, 0]);
+```
+
+`findDifferences([25, 20, 16, 13, 11, 10])` should return `[-5, -4, -3, -2, -1, 0]`.
+
+```js
+assert.deepEqual(findDifferences([25, 20, 16, 13, 11, 10]), [-5, -4, -3, -2, -1, 0]);
+```
+
+`findDifferences([0, 1, 2, 2, 3, 3, 4, 5])` should return `[ 1, 1, 0, 1, 0, 1, 1, 0 ]`.
+
+```js
+assert.deepEqual(findDifferences([0, 1, 2, 2, 3, 3, 4, 5]), [ 1, 1, 0, 1, 0, 1, 1, 0 ]);
+```
+
+`findDifferences([1, 2, 5, 12, 34, -15, -1, 41, 113, -222, -99, -40, 10, -18, -6, -2, -1])` should return `[1, 3, 7, 22, -49, 14, 42, 72, -335, 123, 59, 50, -28, 12, 4, 1, 0]`.
+
+```js
+assert.deepEqual(findDifferences([1, 2, 5, 12, 34, -15, -1, 41, 113, -222, -99, -40, 10, -18, -6, -2, -1]), [1, 3, 7, 22, -49, 14, 42, 72, -335, 123, 59, 50, -28, 12, 4, 1, 0]);
+```
+
+# --seed--
+
+## --seed-contents--
+
+```js
+function findDifferences(arr) {
+
+  return arr;
+}
+```
+
+# --solutions--
+
+```js
+function findDifferences(arr) {
+  const result = [];
+
+  for (let i = 0; i < arr.length; i++) {
+    result.push(arr[i + 1] - arr[i] || 0);
+  }
+
+  return result;
+}
+```

curriculum/challenges/english/blocks/daily-coding-challenges-javascript/698a1a73ade5ac0e19180fa3.md

@@ -0,0 +1,81 @@
+---
+id: 698a1a73ade5ac0e19180fa3
+title: "Challenge 200: Letter and Number Count"
+challengeType: 28
+dashedName: challenge-200
+---
+
+# --description--
+
+Given a string, return a message with the count of how many letters and numbers it contains.
+
+- Letters are `A-Z` and `a-z`.
+- Numbers are `0-9`.
+- Ignore all other characters.
+
+Return `"The string has X letters and Y numbers."`, where `"X"` is the count of letters and `"Y"` is the count of numbers. If either count is 1, use the singular form for that item. E.g: `"1 letter"` instead of `"1 letters"` and `"1 number"` instead of `"1 numbers"`.
+
+# --hints--
+
+`countLettersAndNumbers("helloworld123")` should return `"The string has 10 letters and 3 numbers."`.
+
+```js
+assert.equal(countLettersAndNumbers("helloworld123"), "The string has 10 letters and 3 numbers.");
+```
+
+`countLettersAndNumbers("Catch 22")` should return `"The string has 5 letters and 2 numbers."`.
+
+```js
+assert.equal(countLettersAndNumbers("Catch 22"), "The string has 5 letters and 2 numbers.");
+```
+
+`countLettersAndNumbers("A1!")` should return `"The string has 1 letter and 1 number."`.
+
+```js
+assert.equal(countLettersAndNumbers("A1!"), "The string has 1 letter and 1 number.");
+```
+
+`countLettersAndNumbers("12345")` should return `"The string has 0 letters and 5 numbers."`.
+
+```js
+assert.equal(countLettersAndNumbers("12345"), "The string has 0 letters and 5 numbers.");
+```
+
+`countLettersAndNumbers("password")` should return `"The string has 8 letters and 0 numbers."`.
+
+```js
+assert.equal(countLettersAndNumbers("password"), "The string has 8 letters and 0 numbers.");
+```
+
+# --seed--
+
+## --seed-contents--
+
+```js
+function countLettersAndNumbers(str) {
+
+  return str;
+}
+```
+
+# --solutions--
+
+```js
+function countLettersAndNumbers(str) {
+  let letterCount = 0;
+  let numberCount = 0;
+
+  for (let char of str) {
+    if ((char >= 'A' && char <= 'Z') || (char >= 'a' && char <= 'z')) {
+      letterCount++;
+    } else if (char >= '0' && char <= '9') {
+      numberCount++;
+    }
+  }
+
+  const letterWord = letterCount === 1 ? "letter" : "letters";
+  const numberWord = numberCount === 1 ? "number" : "numbers";
+
+  return `The string has ${letterCount} ${letterWord} and ${numberCount} ${numberWord}.`;
+}
+```