LOJ #2275. 「JXOI2017」顔色

#include <bits/stdc++.h>
#define

using namespace std;
typedef long long ll;
struct node {int l, r, w, f;}tree[A << 2];
int T, n, a[A], first[A], last[A];
void build(int k, int l, int r) {
  tree[k].l = l; tree[k].r = r; tree[k].w = r - l + 1; tree[k].f = 0;
  if (l == r) return;
  int m = (l + r) >> 1;
  build(k << 1, l, m); build(k << 1 | 1, m + 1, r);
  tree[k].w = tree[k << 1].w + tree[k << 1 | 1].w;
}
void down(int k) {
  tree[k << 1].f = tree[k << 1 | 1].f = 1;
  tree[k << 1].w = tree[k << 1 | 1].w = tree[k].f = 0;
}
void change(int k, int l, int r) {
  if (tree[k].l >= l and tree[k].r <= r) {
    tree[k].w = 0; tree[k].f = 1;
    return;
  }
  if (tree[k].f) down(k);
  int m = (tree[k].l + tree[k].r) >> 1;
  if (l <= m) change(k << 1, l, r);
  if (r > m) change(k << 1 | 1, l, r);
  tree[k].w = tree[k << 1].w + tree[k << 1 | 1].w;
}
int ask(int k, int l, int r) {
  if (tree[k].l >= l and tree[k].r <= r) return tree[k].w;
  if (tree[k].f) down(k);
  int m = (tree[k].l + tree[k].r) >> 1, ans = 0;
  if (l <= m) ans += ask(k << 1, l, r);
  if (r > m) ans += ask(k << 1 | 1, l, r);
  return ans;
}
template<class T> void read(T &x) {
  x = 0; char ch = getchar();
  while (!isdigit(ch)) ch = getchar();
  while (isdigit(ch)) x = x * 10 + ch - '0', ch = getchar();
}
pair<int, int> sta[A];

int main(int argc, char const *argv[]) {
  cin >> T;
  while (T--) {
    int top = 0; ll ans = 0; read(n); build(1, 1, n);
    for (int i = 1; i <= n; i++) first[i] = 0, last[i] = 0;
    for (int i = 1; i <= n; i++) {
      read(a[i]);
      if (!first[a[i]]) first[a[i]] = i;
      last[a[i]] = i;
    }
    for (int i = 1; i <= n; i++) {
      if (i == last[a[i]] and first[a[i]] != last[a[i]]) change(1, first[a[i]] + 1, last[a[i]]);
      else sta[++top] = make_pair(a[i], i);
      while (top and last[sta[top].first] <= i) top--;
      int l = top ? sta[top].second : 0;
      if (i != l) ans += ask(1, l + 1, i);
    }
    printf("%lld\n", ans);
  }
  return 0;
}