星空 （狀壓dp）

星空

10.24

思路：

鏈接

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <queue>
#define INF 0x3f3f3f3f
#define N 40010
#define P 18
using namespace std;

int n, k, m, cnt = 0;
bool a[N];
int dis[P][N], b[70];
pair <int, int> p[P];

queue <int> q;

void bfs(pair<int, int> st) {
    for(register int i=0; i<N; i++) dis[st.first][i] = INF;
    q.push(st.second);
    dis[st.first][st.second] = 0;
    while ( !q.empty() ) {
        int x = q.front(); q.pop();
        for(register int i=1; i<=m; i++) {
            if (x - b[i] >= 0 && dis[st.first][x - b[i]] > dis[st.first][x] + 1) {
                dis[st.first][x - b[i]] = dis[st.first][x] + 1;
                q.push(x - b[i]);
            }
            if (x + b[i] <= n && dis[st.first][x + b[i]] > dis[st.first][x] + 1) {
                dis[st.first][x + b[i]] = dis[st.first][x] + 1;
                q.push(x + b[i]);
            }//
        }
    }
}

int dp[1 << P];

int solve(int state) {
    if (dp[state] != -1) return dp[state];
    if (state == 0) return 0;
    int &ret = dp[state]; ret = INF;
    int x = 0; while (!(state & (1 << x))) x++;
    for(int i=x+1; i<2*k; i++)
        if (state & (1 << i)) ret = min(ret, solve(state ^ (1 << x) ^ (1 << i)) + dis[x][p[i].second]);
    return ret;
}

int main() {
    freopen("starlit.in", "r", stdin);
    freopen("starlit.out", "w", stdout);
    scanf("%d %d %d", &n, &k, &m);
    for(int i=1, x; i<=k; i++) scanf("%d", &x), a[x] = true;
    for(register int i=1; i<=m; i++) scanf("%d", &b[i]);
    for(int i=0; i<=n; i++) if (a[i] != a[i+1]) p[cnt] = pair<int, int> (cnt, i), cnt++;
    for(int i=0; i<cnt; i++) bfs(p[i]);
    memset(dp, -1, sizeof dp);
    int ans = solve((1 << cnt) - 1);
    if(ans != INF) printf("%d\n", ans);
    return 0;
}