bzoj 1831

思路：随便猜一猜填的数字是不下降的，反证很好证明，然后就没了。。

#include<bits/stdc++.h>
#define LL long long
#define fi first
#define se second
#define mk make_pair
#define PII pair<int, int>
#define PLI pair<LL, int>
#define ull unsigned long long
using namespace std;

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

int n, k, a[N];
struct Bit {
    int a[101];
    void modify(int x, int val) {
        for(int i = x; i <= 100; i += i & -i)
            a[i] += val;
    }
    int sum(int x) {
        int ans = 0;
        for(int i = x; i; i -= i & -i)
            ans += a[i];
        return ans;
    }
    int query(int l, int r) {
        if(l > r) return 0;
        return sum(r) - sum(l-1);
    }
} b1, b2;

int main() {
    scanf("%d%d", &n, &k);
    for(int i = 1; i <= n; i++)
        scanf("%d", &a[i]);
    for(int i = n; i >= 1; i--)
        if(~a[i]) b2.modify(a[i], 1);

    LL ans = 0;
    for(int i = 1; i <= n; i++) {
        if(~a[i]) {
            b2.modify(a[i], -1);
            b1.modify(a[i], 1);
            ans += b1.query(a[i]+1, 100);
        } else {
            int ret = inf;
            for(int j = 1; j <= 100; j++) {
                ret = min(ret, b1.query(j+1, 100) + b2.query(1, j-1));
            }
            ans += ret;
        }
    }
    printf("%lld
", ans);
    return 0;
}

/*
*/