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Diffstat (limited to 'additive_number.cpp')
-rw-r--r-- | additive_number.cpp | 54 |
1 files changed, 0 insertions, 54 deletions
diff --git a/additive_number.cpp b/additive_number.cpp deleted file mode 100644 index d62c2e5..0000000 --- a/additive_number.cpp +++ /dev/null @@ -1,54 +0,0 @@ -// 306. Additive Number -#include "leetcode.h" - -/* - * an additive number is a string whose digits can form an additive sequence. a - * valid additive seuqnece should contain at least three numbers. except for the - * firs ttwo numbers each subsequent number in the sequence must be the sum of - * the preceding two. given a string containing only digits, return 'true' if it - * is an additive number, or 'false' otherwise. note, numbers in the additive - * sequence cannot have leading zeros, so sequence, 1,2,03, or 1,02,3 is invalid - */ - -class Solution { - string add(string n, string m) { - string res; - int i = n.size() - 1, j = m.size() - 1, carry = 0; - while (i >= 0 || j >= 0) { - int sum = - carry + (i >= 0 ? (n[i--] - '0') : 0) + (j >= 0 ? (m[j--] - '0') : 0); - res.push_back(sum % 10 + '0'); - carry = sum / 10; - } - if (carry) - res.push_back(carry + '0'); - reverse(res.begin(), res.end()); - return res; - } - bool check(string n1, string n2, string n) { - if (n1.size() > 1 && n1[0] == '0' || n2.size() > 1 && n2[0] == '0') - return false; - string sum = add(n1, n2); - if (n == sum) - return true; - if (n.size() <= sum.size() || !sum.compare(n.substr(0, sum.size()))) - return false; - else - return check(n1, sum, n.substr(sum.size())); - } - -public: - bool isAdditiveNumber(string num) { - for (int i = 1; i <= num.size() / 2; i++) - for (int j = 1; j <= (num.size() - i) / 2; j++) - if (check(num.substr(0, i), num.substr(i, j), num.substr(i + j))) - return true; - return false; - } -}; - -int main() { - Solution obj; - printf("%d\n", obj.isAdditiveNumber("112358")); // expect: 1 - printf("%d\n", obj.isAdditiveNumber("199100199")); // expect: 1 -}; |