LeetCode in TypeScript
66. Plus One
Easy
You are given a large integer represented as an integer array digits, where each digits[i] is the ith digit of the integer. The digits are ordered from most significant to least significant in left-to-right order. The large integer does not contain any leading 0’s.
Increment the large integer by one and return the resulting array of digits.
Example 1:
Input: digits = [1,2,3]
Output: [1,2,4]
Explanation: The array represents the integer 123. Incrementing by one gives 123 + 1 = 124. Thus, the result should be [1,2,4].
Example 2:
Input: digits = [4,3,2,1]
Output: [4,3,2,2]
Explanation: The array represents the integer 4321. Incrementing by one gives 4321 + 1 = 4322. Thus, the result should be [4,3,2,2].
Example 3:
Input: digits = [0]
Output: [1]
Explanation: The array represents the integer 0. Incrementing by one gives 0 + 1 = 1. Thus, the result should be [1].
Example 4:
Input: digits = [9]
Output: [1,0]
Explanation: The array represents the integer 9. Incrementing by one gives 9 + 1 = 10. Thus, the result should be [1,0].
Constraints:
1 <= digits.length <= 1000 <= digits[i] <= 9digitsdoes not contain any leading0’s.
Solution
function plusOne(digits: number[]): number[] {
let num = 1
let carry = 0
let sum
for (let i = digits.length - 1; i >= 0; i--) {
if (i === digits.length - 1) {
sum = digits[i] + carry + num
} else {
sum = digits[i] + carry
}
carry = Math.floor(sum / 10)
digits[i] = sum % 10
}
if (carry !== 0) {
return [carry, ...digits]
}
return digits
}
export { plusOne }