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.
问题：非负整型数被数组表示，比如{3,5,6,8,9}表示大数35689，给这个数+1，就是35690，输出新数组
思想：大数加法。注意有进位发生比如9+1本位保存0，前一位要+1，还要考虑最高位是否会再进一位比如9999+1=10000
public int[] plusOne(int[] digits) { int last=digits.length-1; int carry=(digits[last]+1)/10; digits[last]=(digits[last]+1); for(int i=last-1;i>=0;i--){ int n=digits[i]+carry; carry=n/10;//是否有进位 digits[i]=n; } if(carry==1){ int[] output=new int[digits.length+1]; output[0]=1; System.arraycopy(digits, 0, output, 1, digits.length); // for(int i=0;i<digits.length;i++){ // output[i+1]=digits[i]; // } return output; } else return digits; }