水题 1293: [SCOI2009]生日礼物

来源：互联网发布：mac压缩软件哪个好编辑：程序博客网时间：2024/04/28 21:23

本来想找点单调队列做做。。。。然而这个题并不用。。只要双指针就行了。

#include <bits/stdc++.h>using namespace std;typedef long long LL;const int maxn = 1000000;#define mp(x, y) make_pair(x, y)pair<LL, int> p[maxn];int cnt[105];int n, kk;bool check(int pos){cnt[p[pos].second]--;int ok = 1;for(int i = 1; i <= kk && ok; i++) if(!cnt[i]) ok = 0;if(ok) return true;cnt[p[pos].second]++;return false;}void work(){memset(cnt, 0, sizeof cnt);LL x;int m, a = 0, pos, pos2;for(int i = 1; i <= kk; i++) {scanf("%d", &m);for(int j = 1; j <= m; j++) {scanf("%lld", &x);p[a++] = mp(x, i);}}sort(p, p+a);for(pos = 0; pos < a; pos++) {cnt[p[pos].second]++;int ok = 1;for(int j = 1; j <= kk && ok; j++) if(!cnt[j]) ok = 0;if(ok) break;}LL ans = p[pos].first - p[0].first;for(pos++, pos2 = 0; pos < a; pos++) {cnt[p[pos].second]++;while(check(pos2)) pos2++;ans = min(ans, p[pos].first - p[pos2].first);}printf("%lld\n", ans);}int main(){while(scanf("%d%d", &n, &kk) != EOF) {work();}return 0;}

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