Luogu3118：[USACO15JAN]Moovie Mooving

Posted 2020-10-22 Cyhlnj

题面

传送门

Sol

设\(f[S]\)表示看过的电影集合为\(S\)，当前电影的最大结束时间
枚举电影和电影的开始时间转移
可以对开始时间\(sort\)
二分一下转移即可

# include <bits/stdc++.h>
# define IL inline
# define RG register
# define Fill(a, b) memset(a, b, sizeof(a))
using namespace std;
typedef long long ll;
const int _(30);

IL ll Input(){
    RG char c = getchar(); RG ll x = 0, z = 1;
    for(; c < '0' || c > '9'; c = getchar()) z = c == '-' ? -1 : 1;
    for(; c >= '0' && c <= '9'; c = getchar()) x = (x << 1) + (x << 3) + (c ^ 48);
    return x * z;
}

int n, l, d[_], start[_][1010], f[1 << 20], mi[30], ans = -1;

int main(RG int argc, RG char* argv[]){
    n = Input(); l = Input();
    for(RG int i = 1; i <= n; ++i){
        d[i] = Input(); start[i][0] = Input();
        for(RG int j = 1; j <= start[i][0]; ++j) start[i][j] = Input();
        sort(start[i] + 1, start[i] + start[i][0] + 1);
    }
    RG int S = 1 << n; mi[1] = 1;
    for(RG int i = 2; i <= n; ++i) mi[i] = mi[i - 1] << 1;
    for(RG int i = 0; i < S; ++i)
        for(RG int j = 1; j <= n; ++j){
            if(i & mi[j]) continue;
            RG int k = lower_bound(start[j] + 1, start[j] + start[j][0] + 1, f[i]) - start[j];
            if(start[j][k] > f[i]) --k; 
            if(start[j][k] <= f[i]) f[i | mi[j]] = max(f[i | mi[j]], start[j][k] + d[j]);
        }
    for(RG int i = 0; i < S; ++i)
        if(f[i] >= l){
            RG int cnt = 0;
            for(RG int x = i; x; x -= x & -x) ++cnt;
            if(ans != -1) ans = min(ans, cnt);
            else ans = cnt;
        }
    printf("%d\n", ans);
    return 0;
}