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水题，随便统计一下就好
#include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std;typedef long long LL;const int maxn = 100;int lim[maxn],B,K,len;int f[maxn][maxn];void getlim(int num) { len = 0; memset(lim,0,sizeof(lim)); while(num) { lim[len++] = num % B; num /= B; }}int dfs(int now,int cnt,int bound) { if(now == 0) { return cnt == K; } int ret = 0,m = bound ? lim[now - 1] : 1; int ¬e = f[now][cnt]; if(!bound && note != -1) return note; for(int i = 0;i <= m;i++) { if(i == 0) ret += dfs(now - 1,cnt,bound && i == m); else if(i == 1) { if(cnt == K) continue; ret += dfs(now - 1,cnt + 1,bound && i == m); } } if(!bound) note = ret; return ret;}int solve(int num) { getlim(num); memset(f,-1,sizeof(f)); return dfs(len,0,1);}int main() { int X,Y; cin >> X >> Y >> K >> B; cout << solve(Y) - solve(X - 1) << endl; return 0;}
转载于:https://www.cnblogs.com/rolight/p/3892330.html