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Diffstat (limited to 'count_number_powerful_integers.cpp')
-rw-r--r-- | count_number_powerful_integers.cpp | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/count_number_powerful_integers.cpp b/count_number_powerful_integers.cpp new file mode 100644 index 0000000..2d5981d --- /dev/null +++ b/count_number_powerful_integers.cpp @@ -0,0 +1,41 @@ +// 2999. Count the Number of Powerful Integers +#include "leetcode.h" + +/* + * you are given three integers 'start', 'finish', and 'limit'. you are also + * given a 0-indexed string 's' representing a positive integer. a positive + * integer 'x' is called powerful if it ends with 's' and each digit in 'x' is + * at most 'limit'. return the total number of powerful integers in the range + * '[start .. finish]'. a string 'x' is a suffix of a string 'y' if and only if + * 'x' is a substring of 'y' that starts from some index in 'y' and extends to + * the index 'y.length - 1'. + */ + +class Solution { +private: + long long cnt[16]; + long long get_cnt(char l, const string &n, const string &s) { + long long res = cnt[n.size() - 1], i = 0, size = n.size() - s.size(); + do + res += i == size ? n.substr(i) >= s + : cnt[n.size() - i - 1] * (min(l, n[i]) - '1' + (i > 0)); + while (i < size && n[i++] < l); + return res; + } + +public: + long long numberOfPowerfulInt(long long start, long long finish, int limit, + string s) { + for (int i = s.size(); i < 16; ++i) + cnt[i] = i == s.size() ? 1 : cnt[i - 1] * (limit + 1); + return get_cnt(limit + '1', to_string(finish), s) - + get_cnt(limit + '1', to_string(start - 1), s); + } +}; + +int main() { + Solution obj; + printf("%lld\n", obj.numberOfPowerfulInt(1, 6000, 4, "124")); // expect: 5 + printf("%lld\n", obj.numberOfPowerfulInt(15, 215, 6, "")); // expect: 2 + printf("%lld\n", obj.numberOfPowerfulInt(1000, 2000, 4, "3000")); // expect: 0 +} |