LightOJ 1032 - Fast Bit Calculations（dp）

代码

#include <cstdio>
#include <cstring>
#include <algorithm>

using namespace std;
typedef long long ll;
const int maxn = 50;

ll dp[maxn + 5][maxn + 5][2];

int main () {
int cas;
scanf("%d", &cas);
for (int kcas = 1; kcas <= cas; kcas++) {
int n, bit[maxn + 5];
scanf("%d", &n);
for (int i = maxn; i >= 0; i--) {
bit[i] = (n&1);
n >>= 1;
}

int p = 0;
memset(dp, 0, sizeof(dp));
for (int i = 1; i <= maxn; i++) {
for (int k = 0; k < maxn; k++) {
for (int x = 0; x < 2; x++)
for (int y = 0; y < 2; y++) {
int v = k + (x&y);
dp[i][v][y] += dp[i-1][k][x];
}
}
for (int j = 0; j < bit[i]; j++)
dp[i][p][j]++;
if (bit[i-1] && bit[i]) p++;
}
ll ret = p;
for (int i = 0; i < maxn; i++)
ret += (dp[maxn][i][0] + dp[maxn][i][1]) * i;
printf("Case %d: %lld\n", kcas, ret);
}
return 0;
}