F. Cooking Time 贪心

Posted 2020-10-09 stupid_one

http://codeforces.com/gym/101498/problem/F

对于知道使用情况的置换算法，最优解是找一个最后需要使用的物品替换掉

也就是，如果一个物品后面已经不需要用到，就要拿出来了，碍地方

#include <bits/stdc++.h>
#define ios ios::sync_with_stdio(false)
using namespace std;
#define inf (0x3f3f3f3f)
typedef long long int LL;
const int maxn = 1e5 + 20;
int a[maxn], b[maxn];
int pos[maxn], last[maxn];

typedef pair<int, int> pii;
int tim[maxn], in[maxn], DFN;
struct cmp {
    bool operator () (const pii &a, const pii &b) {
        if (a.first != b.first) return a.first > b.first;
        else return a.second > b.second;
    }
};
set< pair<int, int>, cmp> ss;
void work() {
    ss.clear();
    int n, k;
    scanf("%d%d", &n, &k);
    for (int i = 1; i <= n; ++i) {
        scanf("%d", a + i);
        b[i] = a[i];
        last[i] = n + 1;
    }
    sort(a + 1, a + 1 + n);
    for (int i = 1; i <= n; ++i) {
        b[i] = lower_bound(a + 1, a + 1 + n, b[i]) - a;
//        printf("%d ", b[i]);
    }
//    printf("\n");
    for (int i = n; i >= 1; --i) {
        pos[i] = last[b[i]];
        last[b[i]] = i;
    }
    int fuck = n + 1;
    for (int i = 1; i <= n; ++i) {
        if (pos[i] == n + 1) pos[i] = fuck++;
    }
    int ans = 0;
    ++DFN;
    set< pair<int, int> > :: iterator it;
    for (int i = 1; i <= n; ++i) {
        if (in[b[i]] == DFN) {
            ss.erase(make_pair(tim[b[i]], b[i]));
            ss.insert(make_pair(pos[i], b[i]));
            tim[b[i]] = pos[i];
            continue;
        }
        if (ss.size() == k) {
            it = ss.begin();
            in[it->second] = DFN - 1;
            ss.erase(it);
        }
        ss.insert(make_pair(pos[i], b[i]));
        in[b[i]] = DFN;
        tim[b[i]] = pos[i];
        ans++;
    }
    printf("%d\n", ans);
}

int main() {
#ifdef local
    freopen("data.txt", "r", stdin);
//    freopen("data.txt", "w", stdout);
#endif
    int t;
    scanf("%d", &t);
    while (t--) work();
    return 0;
}

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