P1886 滑动窗口 /【模板】单调队列

R43006059

problem/P1886/P1886.cpp

@@ -3,35 +3,80 @@
 using namespace std;
 
 struct node {
-    int key, val;
-} a[1000005];
+    int l, r;
+    int min, max;
 
-int n, k;
-deque<node> q;
+    node() {
+        l = r = 0;
+        min = 0x3f3f3f3f;
+        max = -0x3f3f3f3f;
+    }
+    node(int _l, int _r) {
+        l = _l;
+        r = _r;
+        min = 0x3f3f3f3f;
+        max = -0x3f3f3f3f;
+    }
+} tr[1000005 << 2];
+int n, k, a[1000005];
+
+void pushup(int u) {
+    tr[u].max = max(tr[u << 1].max, tr[u << 1 | 1].max);
+    tr[u].min = min(tr[u << 1].min, tr[u << 1 | 1].min);
+}
+
+void build(int u, int l, int r) {
+    tr[u] = node(l, r);
+    if (l == r) {
+        tr[u].max = tr[u].min = a[l];
+        return;
+    }
+    int mid = l + r >> 1;
+    build(u << 1, l, mid);
+    build(u << 1 | 1, mid + 1, r);
+    pushup(u);
+}
+
+pair<int, int> query(int u, int l, int r) {
+    if (l <= tr[u].l && r >= tr[u].r) {
+        return make_pair(tr[u].max, tr[u].min);
+    }
+    int mid = tr[u].l + tr[u].r >> 1;
+    pair<int, int> ans, tmp;
+    ans.first = -0x3f3f3f3f;
+    ans.second = 0x3f3f3f3f;
+    if (l <= mid) {
+        tmp = query(u << 1, l, r);
+        ans.first = max(ans.first, tmp.first);
+        ans.second = min(ans.second, tmp.second);
+    }
+    if (r > mid) {
+        tmp = query(u << 1 | 1, l, r);
+        ans.first = max(ans.first, tmp.first);
+        ans.second = min(ans.second, tmp.second);
+    }
+    return ans;
+}
 
 int main() {
-    cin >> n >> k;
+    scanf("%d%d", &n, &k);
     for (int i = 1; i <= n; i++) {
-        a[i].key = i;
-        cin >> a[i].val;
+        scanf("%d", &a[i]);
     }
-    // 最小值
-    for (int i = 1; i <= n; i++) {
-        while (!q.empty() && a[i].val <= q.front().val) q.pop_front();
-        q.push_front(a[i]);
-        while (q.back().key <= i - k) q.pop_back();
-        if (i >= k) cout << q.back().val << ' ';
+    build(1, 1, n);
+    vector<int> ans_min, ans_max;
+    for (int i = 1; i + k - 1 <= n; i++) {
+        pair<int, int> tmp = query(1, i, i + k - 1);
+        ans_max.push_back(tmp.first);
+        ans_min.push_back(tmp.second);
     }
-    q.clear();
-    cout << endl;
-    // 最大值
-    for (int i = 1; i <= n; i++) {
-        while (!q.empty() && a[i].val >= q.front().val) q.pop_front();
-        q.push_front(a[i]);
-        while (q.back().key <= i - k) q.pop_back();
-        if (i >= k) cout << q.back().val << ' ';
+    for (int i = 0; i < ans_min.size(); i++) {
+        printf("%d ", ans_min[i]);
     }
-    q.clear();
-    cout << endl;
+    printf("\n");
+    for (int i = 0; i < ans_max.size(); i++) {
+        printf("%d ", ans_max[i]);
+    }
+    printf("\n");
     return 0;
 }