2562-count-ways-to-build-good-strings.cpp

classSolution {
private:
int MOD = 1e9 + 7;
intsolve(int i, int l, int h, int z, int o, vector<int>& dp) {
if (i > h) return0;
if (dp[i] != -1) return dp[i];
int cur = 0;
if (i >= l && i <= h) ++cur;
 cur += solve(i + z, l, h, z, o, dp);
 cur = (cur % MOD + solve(i + o, l, h, z, o, dp) % MOD) % MOD;
return dp[i] = cur % MOD;
 }
public:
intcountGoodStrings(int low, int high, int zero, int one) {
 vector<int> dp(high + 1, -1);
returnsolve(0, low, high, zero, one, dp);
 }
};