主席树算贡献l,r中交换位置，算出>=rank(h) 和 <=rank(h)  a[l],a[r] 先不统计 a[l]比a[r]大的话交换后ans-1，a[l]比a[r]小的话交换后ans-1，ans+<r的，->r的 ans-<l的，+>l的，区间比k大的数量或者区间第k大等类似的可以用第二类主席树弄

#include <cstdio>
#include <memory>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <vector>
#include <cassert>
#include <string>
#include <ctime>
#include <map>
#include <queue>
#include <algorithm>
#include <iostream>
#include <cassert>
#include <set>
using namespace std;
#define REP(i,n) for(int i=0;i<n;i++)
#define rep(i,a,b) for(int i=a;i<=b;i++)
#define req(i,a,b) for(int i=a;i>=b;i--)
#define rp(i,a) for(int i=head[a];i+1;i=edge[i].next)
#define cl(a,b) memset(a,b,sizeof a);
#define ll long long
#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1
#define mod 10007
const int inf = ~0u >> 2;
const ll INF = (1LL << 62) - 1;
double eps = 1e-12;
const int N = 500005 + 5;
const int M = 200005;int n, m, d;
int a[500005];
int rnk[N];
int root[N];
int croot[N];
int sz = 0, tot = 0;
void insert(int &num, int val, int k, int l, int r);
struct Node {int sum;int ch[2];
}T[30500010];
void insert(int &num, int val, int k, int l, int r, int flag) {if (flag == 0 || num == 0) {T[++sz] = T[num]; num = sz;}T[num].sum += val;if (l == r) {return;}int m = (l + r) >> 1;if (k <= m) {insert(T[num].ch[0], val, k, l, m, flag);}else {insert(T[num].ch[1], val, k, m + 1, r, flag);}
}
int query(int i, int j, int k, int l, int r) {if (k > T[j].sum - T[i].sum)k = T[i].sum - T[i].sum;if (l == r)return l;int m = (l + r) >> 1;if (k <= T[T[j].ch[0]].sum - T[T[i].ch[0]].sum)return query(T[i].ch[0], T[j].ch[0], k, l, m);elsereturn query(T[i].ch[1], T[j].ch[1], k - (T[T[j].ch[0]].sum - T[T[i].ch[0]].sum), m + 1, r);
}
void add(int x, int num, int d) {while (x <= tot) {insert(croot[x], d, num, 1, tot, 1);x += x&-x;}
}
struct Pack {vector<int> v;Pack() {}Pack(int x) { v.push_back(x); }void operator +=(int x) {v.push_back(x);}operator ll()const {//得到左孩子和ll ret = 0;for (int i = 0; i<v.size(); i++)ret += T[T[v[i]].ch[0]].sum;return ret;}void lt() {for (int i = 0; i < v.size(); i++)v[i] = T[v[i]].ch[0];}void rt() {for (int i = 0; i < v.size(); i++)v[i] = T[v[i]].ch[1];}
};
Pack sum(int x, int k) {Pack ret;while (x>0) {ret += croot[x];x -= x&-x;}return ret;
}
ll binSearch(int l, int r, int k) {Pack treesl = sum(l,0);Pack treesr = sum(r,0);Pack presl = Pack(root[l]);Pack presr = Pack(root[r]);int xl = 1, xr = tot;ll ret = 0;int rtl = root[l];int rtr = root[r];while (xl < xr) {int mid = (xl + xr) >> 1;ll t = treesr - treesl + presr - presl;if (mid <= k) {ret += t;treesr.rt(); treesl.rt(); presr.rt(); presl.rt();//ret += T[T[rtr].ch[0]].sum - T[T[rtl].ch[0]].sum;xl = mid+1;if (mid == k) {ret--;break;}}else {treesr.lt(); treesl.lt(); presr.lt(); presl.lt();xr = mid;}}return ret;
}
struct Seg {int l, r, h, x;
}q[M];
int val[N];
int cnt = 0;
int Hash(int x) {return lower_bound(val, val + tot, x) - val + 1;
}
int b[N];
int main() {//for (int i = 0; i <= sz; i++)T[i] = T[0];cnt = 0;sz = 0;tot = 0;scanf("%d%d", &n, &m);for (int i = 1; i <= n; i++) {a[i] = i;b[i] = i;val[cnt++] = a[i];}for (int i = 0; i < m; i++) {int x, y;scanf("%d%d", &x, &y);if (x > y)swap(x, y);q[i * 4].l = x;q[i * 4].r = y;q[i * 4].h = b[y];q[i * 4].x = -1;q[i * 4 + 1].l = x;q[i * 4 + 1].r = y;q[i * 4 + 1].h = b[x];q[i * 4 + 1].x = -2;q[i*4+2].x = x;q[i*4+2].h = b[y];//val[cnt++] = b[y];q[i*4+2].l = -inf;q[i * 4+3].x = y;q[i * 4+3].h = b[x];//val[cnt++] = b[x];q[i * 4+3].l = -inf;swap(b[x], b[y]);/*if (l<1 || r>n || l>r || h<1 || h>r - l + 1)assert(false);*/}sort(val, val + cnt);rnk[0] = ++tot;for (int i = 1; i < cnt; i++) {if (val[i] != val[i - 1])rnk[i] = ++tot;elsernk[i] = tot;}for (int i = 0; i <= tot; i++)croot[i] = 0;unique(val, val + cnt);root[0] = 0;for (int i = 1; i <= n; i++) {root[i] = root[i - 1];insert(root[i], 1, Hash(a[i]), 1, tot, 0);}ll ans = 0;for (int i = 0; i < 4*m; i++) {if (q[i].l != -inf) {if (q[i].x == -1) {if (q[i].l != q[i].r) {ll tmp = binSearch(q[i].l - 1, q[i].r, Hash(q[i].h));if (a[q[i].l] < a[q[i].r])tmp--;ans += tmp;ans -= max(0LL, (q[i].r - q[i].l - tmp - 1));}//printf("%d\n", val[binSearch(q[i].l - 1, q[i].r, q[i].h) - 1]);}if (q[i].x == -2) {if (q[i].l != q[i].r) {ll tmp = binSearch(q[i].l - 1, q[i].r, Hash(q[i].h));if (a[q[i].l] > a[q[i].r])tmp--;ans -= tmp;ans += max(0LL, (q[i].r - q[i].l - tmp - 1));}if (a[q[i].l] > a[q[i].r])ans--;else if(a[q[i].l]<a[q[i].r])ans++;cout << ans << endl;}}else {add(q[i].x, Hash(a[q[i].x]), -1);a[q[i].x] = q[i].h;add(q[i].x, Hash(q[i].h), 1);}}//cout << ans << endl;/*for (int i = 1; i <= tot; i++)croot[i] = 0, val[i] = 0, a[i] = 0;*/return 0;
}