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Diffstat (limited to 'other/count_ways_build_strs.cpp')
-rw-r--r-- | other/count_ways_build_strs.cpp | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/other/count_ways_build_strs.cpp b/other/count_ways_build_strs.cpp new file mode 100644 index 0000000..d388b2f --- /dev/null +++ b/other/count_ways_build_strs.cpp @@ -0,0 +1,38 @@ +// 2466. Count Ways To Build Good Strings +#include "leetcode.h" + +/* + * given the integers 'zero, one, low, and high', we can construct a string by + * starting with an empty string, and then at each step perform either of the + * following opperations: + * - append the character 0 'zero' times + * - append the character 1 'one' times + * this can be performed any number of times. a good string is a string + * constructed by the above process having a length between 'low' and 'high' + * (inclusive). return the number of different good strings that can be + * constructed. return modulo 10^9+7. + */ + +class Solution { +public: + int countGoodStrings(int low, int high, int zero, int one) { + int mod = 1e9 + 7, ans = 0; + vector<int> dp(high + 1, 0); + dp[0] = 1; + for (int i = 1; i <= high; i++) { + if (i >= one) + dp[i] = (dp[i] + dp[i - one]) % mod; + if (i >= zero) + dp[i] = (dp[i] + dp[i - zero]) % mod; + if (i >= low) + ans = (ans + dp[i]) % mod; + } + return ans; + } +}; + +int main() { + Solution obj; + printf("%d\n", obj.countGoodStrings(3, 3, 1, 1)); // expect: 8 + printf("%d\n", obj.countGoodStrings(2, 3, 1, 2)); // expect: 5 +} |