CodeForces 830B - Cards Sorting

将每个数字的位置存进该数字的vector中

原数组排个序从小到大处理，每次在vector里二分找到距离当前位置“最远”的位置（相差最大），更新答案

树状数组维护每个数字现在的位置和原位置之差

 #include <bits/stdc++.h>
 using namespace std;
 #define LL long long
 const int N = ;
 int n;
 int a[N], b[N];
 vector<int> v[N];
 int c[N];
 void modify(int x, int num)
 {
     while (x <= ) c[x] += num, x += x&-x;
 }
 int sum(int x)
 {
     int s = ;
     while (x) s += c[x], x -= x&-x;
     return s;
 }
 int main()
 {
     scanf("%d", &n);
     for (int i = ; i <= n; i++) scanf("%d", &a[i]), b[i] = a[i];
     sort(b+, b++n);
     for (int i = ; i <= n; i++)
         v[a[i]].push_back(i);
     LL ans = ;
     int now = ;
     for (int i = ; i <= n;)
     {
         int p = lower_bound(v[b[i]].begin(), v[b[i]].end(), now) - v[b[i]].begin();
         if (p == )
         {
             int pos = v[b[i]][v[b[i]].size()-];
             ans += pos - sum(pos) - (now - sum(now));
             now = pos;
         }
         else
         {
             int pos = v[b[i]][p-];
             ans += n - sum(n) - (now-sum(now)) + pos - sum(pos);
             now = pos;
         }
         for (int j = ; j < v[b[i]].size(); j++) modify(v[b[i]][j], );
         i += v[b[i]].size();
     }
     cout << ans << endl;
 }