本文共 2468 字，大约阅读时间需要 8 分钟。

题目链接：https://vjudge.net/problem/UVA-11990
过几天我再来写题解

#include<map>#include<set>#include<cmath>#include<queue>#include<stack>#include<vector>#include<cstdio>#include<cstdlib>#include<cstring>#include<iostream>#include<algorithm>#define ll long long#define ll long longusing namespace std;const int MAX = 2e5 + 10;struct node{       int t, v, index;    bool flag;};node a[MAX], b[MAX];int pos[MAX];int ans[MAX];int bit[MAX];int n, m;int sum(int i) {       int s = 0;    while (i > 0) {           s += bit[i];        i -= i & (-i);    }    return s;}void add(int i, int x) {       while(i <= n) {           bit[i] += x;        i += i & (-i);    }}bool cmpt(node a, node b){       return a.t < b.t;}bool cmpx(node a, node b){       return a.index < b.index;}void cdq(int L, int R) {       if(L >= R) return;    int mid = (L + R) / 2;    int len = 0;    for(int i = L; i <= mid; i++) {           b[++len] = a[i];        b[len].flag = 0;    }    for(int i = mid + 1; i <= R; i++) {           b[++len] = a[i];        b[len].flag = 1;    }    sort(b + 1, b + len + 1, cmpx);    for(int i = 1; i <= len; i++) {           if(b[i].flag == 0)            add(b[i].v, 1);        else            ans[b[i].t] += sum(n) - sum(b[i].v);    }    for(int i = 1; i <= len; i++) {           if(b[i].flag == 0)            add(b[i].v, -1);    }    for(int i = len; i >= 1; i--) {           if(b[i].flag == 0)            add(b[i].v, 1);        else ans[b[i].t] += sum(b[i].v);    }    for(int i = 1; i <= len;i++) {           if(b[i].flag == 0)            add(b[i].v, -1);    }    cdq(L, mid);    cdq(mid + 1, R);}int main() {       while (scanf("%d%d", &n, &m) != EOF) {           memset(a, 0, sizeof(a));        memset(b, 0, sizeof(b));        memset(ans, 0, sizeof(ans));        memset(pos, 0, sizeof(pos));        memset(bit, 0, sizeof(bit));        for(int i = 1; i <= n; i++) {               scanf("%d", &a[i].v);            pos[a[i].v] = i;            a[i].index = i;        }        int T = n;        for(int i = 1; i <= m; i++) {               int x;            scanf("%d", &x);            a[pos[x]].t = T--;        }        for(int i = 1; i <= n; i++) {               if(!a[i].t) a[i].t = T--;        }        sort(a + 1, a + n + 1, cmpt);        cdq(1, n);        ll res = 0;//int res 是错的        for(int i = 1; i <= n; i++) res += ans[i];        for(int i = n; i >= n - m + 1; i--) {               printf("%lld\n", res);            res -= ans[i];        }    }}//5 4 1 5 3 4 2 5 1 4 2