Codeforces - 1199C - MP3 - 尺取

https://codeforc.es/contest/1199/problem/C

擦，最后移位运算符溢出了，真的蠢。

肯定是选中间的连续的某段是最优的，维护这个段的长度和其中的元素种类就可以了。小心x可能很大导致溢出。

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;

inline int read() {
    int x = 0;
    int f = 0;
    char c;
    do {
        c = getchar();
        if(c == '-')
            f = 1;
    } while(c < '0' || c > '9');
    do {
        x = (x << 3) + (x << 1) + c - '0';
        c = getchar();
    } while(c >= '0' && c <= '9');
    return f ? -x : x;
}

inline void _write(int x) {
    if(x > 9)
        _write(x / 10);
    putchar(x % 10 + '0');
}

inline void write(int x) {
    if(x < 0) {
        putchar('-');
        x = -x;
    }
    _write(x);
    putchar('\n');
}

int n, I, x, len;
int a[400005];

map<int, int> m;

int main() {
#ifdef Yinku
    freopen("Yinku.in", "r", stdin);
#endif // Yinku
    n = read(), I = read();
    x = (8 * I) / n;
    if(x >= 30)
        x = 30;
    len = (1 << x);
    for(int i = 1; i <= n; ++i)
        a[i] = read();
    sort(a + 1, a + 1 + n);
    int l = 1, r = 1;
    m[a[1]]++;
    int cnt1 = 1, cnt2 = 1, ans = n - 1;
    while(r < n) {
        r++;
        int t = m[a[r]]++;
        cnt2++;
        if(t == 0)
            cnt1++;
        while(cnt1 > len) {
            int tmp = m[a[l]]--;
            if(tmp == 1)
                cnt1--;
            l++;
            cnt2--;
        }
        ans = min(ans, n - cnt2);
    }
    printf("%d\n", ans);
}