【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 = 65;
int mask[maxn];
bool visit[maxn];
int P[maxn];
const int m = 16;
const int N = (1<<m)+5;
const int INF = 0x1f1f1f1f;
int dp[105][N];
int path[105][N];
int a[105];

void init() {
    int i, j, k = 0;
    
    for (i=2; i<maxn; ++i) {
        if (!visit[i]) {
            P[k++] = i;
            for (j=i*i; j<maxn; j+=i)
                visit[j] = true;
        }
    }
    
    for (i=1; i<maxn; ++i) {
        for (j=0; j<m; ++j) {
            if (i%P[j] == 0) {
                mask[i] |= (1<<j);
            }
        }
    }
    
    #ifndef ONLINE_JUDGE
        printf("P[%d] = %d
", 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, 1, n+1)
        scanf("%d", &a[i]);
    
    int i, j, k;
    int st, tmp;
    int mxs = 1<<16;
    
    memset(dp, 0x1f, sizeof(dp));
    memset(dp[0], 0, sizeof(int)*N);
    for (i=1; i<=n; ++i) {
        for (j=0; j<mxs; ++j) {
            for (k=1; k<=60; ++k) {
                if (j & mask[k])
                    continue;
                tmp = dp[i-1][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=0; j<mxs; ++j) {
        if (dp[n][j] < mn) {
            mn = dp[n][j];
            v = j;
        }
    }
    
    vi ans;
    
    for (i=n; i>0; --i) {
        k = path[i][v];
        ans.pb(k);
        v ^= mask[k];
    }
    
    for (i=n-1; i>=0; --i)
        printf("%d ", ans[i]);
    putchar('
');
    
    #ifndef ONLINE_JUDGE
        printf("time = %d.
", (int)clock());
    #endif
    
    return 0;
}