【CF】259 Div.1 B Little Pony and Harmony Chest

还蛮有趣的一道状态DP的题目。

 /* 435B */
 #include <iostream>
 #include <string>
 #include <map>
 #include <queue>
 #include <set>
 #include <stack>
 #include <vector>
 #include <deque>
 #include <algorithm>
 #include <cstdio>
 #include <cmath>
 #include <ctime>
 #include <cstring>
 #include <climits>
 #include <cctype>
 #include <cassert>
 #include <functional>
 #include <iterator>
 #include <iomanip>
 using namespace std;
 //#pragma comment(linker,"/STACK:102400000,1024000")
 
 #define sti                set<int>
 #define stpii            set<pair<int, int> >
 #define mpii            map<int,int>
 #define vi                vector<int>
 #define pii                pair<int,int>
 #define vpii            vector<pair<int,int> >
 #define rep(i, a, n)     for (int i=a;i<n;++i)
 #define per(i, a, n)     for (int i=n-1;i>=a;--i)
 #define clr                clear
 #define pb                 push_back
 #define mp                 make_pair
 #define fir                first
 #define sec                second
 #define all(x)             (x).begin(),(x).end()
 #define SZ(x)             ((int)(x).size())
 #define lson            l, mid, rt<<1
 #define rson            mid+1, r, rt<<1|1
 
 const int maxn = ;
 int mask[maxn];
 bool visit[maxn];
 int P[maxn];
 const int m = ;
 const int N = (<<m)+;
 const int INF = 0x1f1f1f1f;
 int dp[][N];
 int path[][N];
 int a[];
 
 void init() {
     int i, j, k = ;
 
     for (i=; i<maxn; ++i) {
         if (!visit[i]) {
             P[k++] = i;
             for (j=i*i; j<maxn; j+=i)
                 visit[j] = true;
         }
     }
 
     for (i=; i<maxn; ++i) {
         for (j=; j<m; ++j) {
             if (i%P[j] == ) {
                 mask[i] |= (<<j);
             }
         }
     }
 
     #ifndef ONLINE_JUDGE
         printf("P[%d] = %d\n", m, P[m]);
     #endif
 }
 
 int main() {
     ios::sync_with_stdio(false);
     #ifndef ONLINE_JUDGE
         freopen("data.in", "r", stdin);
         freopen("data.out", "w", stdout);
     #endif
 
     init();
     int n;
 
     scanf("%d", &n);
     rep(i, , n+)
         scanf("%d", &a[i]);
 
     int i, j, k;
     int st, tmp;
     int mxs = <<;
 
     memset(dp, 0x1f, sizeof(dp));
     memset(dp[], , sizeof(int)*N);
     for (i=; i<=n; ++i) {
         for (j=; j<mxs; ++j) {
             for (k=; k<=; ++k) {
                 if (j & mask[k])
                     continue;
                 tmp = dp[i-][j] + abs(a[i] - k);
                 st = j | mask[k];
                 if (dp[i][st] > tmp) {
                     dp[i][st] = tmp;
                     path[i][st] = k;
                 }
             }
         }
     }
 
     int mn = INT_MAX, v;
 
     for (j=; j<mxs; ++j) {
         if (dp[n][j] < mn) {
             mn = dp[n][j];
             v = j;
         }
     }
 
     vi ans;
 
     for (i=n; i>; --i) {
         k = path[i][v];
         ans.pb(k);
         v ^= mask[k];
     }
 
     for (i=n-; i>=; --i)
         printf("%d ", ans[i]);
     putchar('\n');
 
     #ifndef ONLINE_JUDGE
         printf("time = %d.\n", (int)clock());
     #endif
 
     return ;
 }