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66 Plus One

66. Plus One

1. Question

Given a non-negative integer represented as a non-empty array of digits, plus one to the integer.
You may assume the integer do not contain any leading zero, except the number 0 itself.
The digits are stored such that the most significant digit is at the head of the list.

2. Implementation

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class Solution {
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public int[] plusOne(int[] digits) {
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int n = digits.length;
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for (int i = n - 1; i >= 0; i--) {
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if (digits[i] != 9) {
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digits[i] += 1;
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return digits;
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}
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else {
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digits[i] = 0;
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}
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}
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int[] res = new int[n + 1];
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res[0] = 1;
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return res;
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}
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}
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3. Time & Space Complexity

时间复杂度O(n), 空间复杂度O(n)