bzoj 1293: [SCOI2009]生日礼物

思路：尺取一下

#include<bits/stdc++.h>
#define LL long long
#define fi first
#define se second
#define mk make_pair
#define pii pair<int,int>
#define piii pair<int, pair<int,int>>

using namespace std;

const int N = 1e6 + 7;
const int M = 1e4 + 7;
const int inf = 0x3f3f3f3f;
const LL INF = 0x3f3f3f3f3f3f3f3f;
const int mod = 1e9 + 7;

int n, k, hs[N], tot, cnt[66];
vector<int> vec[66];
vector<int> w[N];
LL a[N];

int check() {
    int l = 0, r = 0, ans = inf;
    LL ret = 0;
    while(r < tot) {
        while(ret + 1 != 1ll << k && r < tot) {
            for(int j = 0; j < w[r].size(); j++) {
                int u = w[r][j];
                if(!cnt[u]) {
                    ret |= 1ll << u;
                }
                cnt[u]++;
            }
            r++;
        }
        if(ret + 1 == 1ll << k) ans = min(ans, hs[r - 1] - hs[l]);
        else break;

        for(int j = 0; j < w[l].size(); j++) {
            int u = w[l][j];
            if(cnt[u] == 1) {
                ret ^= 1ll << u;
            }
            cnt[u]--;
        }
        l++;
    }
    return ans;
}

int main() {
    scanf("%d%d", &n, &k);
    for(int i = 0; i < k; i++) {
        int num; scanf("%d", &num);
        while(num--) {
            int x; scanf("%d", &x);
            hs[tot++] = x;
            vec[i].push_back(x);
        }
    }

    sort(hs, hs + tot);
    tot = unique(hs, hs + tot) - hs;
    for(int i = 0; i < k; i++) {
        for(int j = 0; j < vec[i].size(); j++) {
            int pos = lower_bound(hs, hs + tot, vec[i][j]) - hs;
            w[pos].push_back(i);
        }
    }
    int ans = check();
    printf("%d\n", ans);
    return 0;
}

/*
*/