2815. 三维偏序

https://www.acwing.com/problem/content/submission/code_detail/14402368/

AcWing/2815/2815.cpp

@@ -0,0 +1,111 @@
+#include <algorithm>
+#include <iostream>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 2e5 + 5;
+
+struct node {
+    int a, b, c, cnt, res;
+
+    node()
+        : a(0), b(0), c(0), cnt(0), res(0) {}
+
+    node(int _a, int _b, int _c)
+        : a(_a), b(_b), c(_c), cnt(1), res(0) {}
+
+    bool operator<(const node& x) const {
+        return a == x.a ? b == x.b ? c < x.c : b < x.b : a < x.a;
+    }
+
+    bool operator==(const node& x) const {
+        return a == x.a && b == x.b && c == x.c;
+    }
+} q[N], w[N];
+
+int n, k, ans[N];
+int c[N];
+
+inline int lowbit(int x) {
+    return x & -x;
+}
+
+void add(int x, int y) {
+    for (; x <= 2e5; x += lowbit(x)) c[x] += y;
+}
+
+int sum(int x) {
+    int res = 0;
+    for (; x; x -= lowbit(x)) res += c[x];
+    return res;
+}
+
+void merge_sort(int l, int r) {
+    if (l >= r) return;
+
+    int mid = l + r >> 1;
+
+    merge_sort(l, mid);
+    merge_sort(mid + 1, r);
+
+    int i = l, j = mid + 1, k = 0;
+    while (i <= mid && j <= r) {
+        if (q[i].b <= q[j].b) {
+            add(q[i].c, q[i].cnt);
+            w[++k] = q[i++];
+        } else {
+            q[j].res += sum(q[j].c);
+            w[++k] = q[j++];
+        }
+    }
+
+    while (i <= mid) {
+        add(q[i].c, q[i].cnt);
+        w[++k] = q[i++];
+    }
+
+    while (j <= r) {
+        q[j].res += sum(q[j].c);
+        w[++k] = q[j++];
+    }
+
+    for (int i = l; i <= mid; i++) add(q[i].c, -q[i].cnt);
+    for (int i = l, j = 1; j <= k; i++, j++) q[i] = w[j];
+}
+
+int main() {
+    std::ios::sync_with_stdio(false);
+
+    cin >> n >> k;
+
+    for (int i = 1, a, b, c; i <= n; i++) {
+        cin >> a >> b >> c;
+
+        q[i] = node(a, b, c);
+    }
+
+    std::sort(q + 1, q + 1 + n);
+
+    int k = 1;
+    for (int i = 2; i <= n; i++) {
+        if (q[i] == q[k]) {
+            q[k].cnt++;
+        } else {
+            q[++k] = q[i];
+        }
+    }
+
+    merge_sort(1, k);
+
+    for (int i = 1; i <= k; i++) {
+        ans[q[i].res + q[i].cnt - 1] += q[i].cnt;
+    }
+
+    for (int i = 0; i < n; i++) {
+        cout << ans[i] << endl;
+    }
+
+    return 0;
+}