2410. 2의 멱수의 합 - DP

baekjoon/cpp/c++/2410.cpp

@@ -0,0 +1,64 @@
+#include <bits/stdc++.h>
+
+const int MOD = 1e9;
+
+int n;
+int dp[1000001][21], mlog[1000001];
+
+void getinput()
+{
+ std::cin >> n;
+}
+
+void init()
+{
+ for (int i = 0; i <= 20; i++)
+ {
+ if ((1 << i) <= 1000000)
+ {
+ mlog[1 << i] = i;
+ }
+ }
+
+ for (int i = 1; i <= 1000000; i++)
+ {
+ if (mlog[i] == 0)
+ {
+ mlog[i] = mlog[i - 1];
+ }
+ }
+}
+
+int solve(int n, int sq)
+{
+ if (n == 0)
+ return 1;
+ auto &ret = dp[n][sq];
+ if (ret != -1)
+ return ret;
+
+ ret = 0;
+ for (int i = std::min(sq, mlog[n]); i >= 0; i--)
+ {
+ auto tans = solve(n - (1 << i), i);
+ ret = (ret + tans) % MOD;
+ }
+ return ret;
+}
+
+int solve()
+{
+ std::memset(dp, -1, sizeof(dp));
+ init();
+
+ return solve(n, mlog[n]);
+}
+
+int main()
+{
+ std::ios::sync_with_stdio(false);
+ std::cin.tie(0);
+
+ getinput();
+ std::cout << solve() << '\n';
+}