0066-plus-one.c

int* plusOne(int* digits, int digitsSize, int* returnSize) {
    for(int i = digitsSize - 1; i >= 0; i--) {
        if(digits[i] < 9) {
            digits[i]++;
            *returnSize = digitsSize;
            return digits;
        } else {
            digits[i] = 0;
        }
    }
    int* res = (int*)malloc(sizeof(int) * (digitsSize + 1));
    res[0] = 1;
    for(int i = 1; i < (digitsSize + 1); i++) {
        res[i] = 0;
    }
    *returnSize = digitsSize + 1;
    return res;
}