new file: P1168.cpp

P1168.cpp

@@ -0,0 +1,44 @@
+// 106
+#include <bits/stdc++.h>
+using namespace std;
+int n;
+int a[100005], ord[100005], pos[100005];
+int pre[100005], nxt[100005];
+int ans[100005];
+
+int main()
+{
+    scanf("%d", &n);
+    for (int i = 1; i <= n; ++i)
+        scanf("%d", &a[i]), ord[i] = i;
+    sort(ord + 1, ord + n + 1, [](int x, int y)
+         { return a[x] != a[y] ? a[x] < a[y] : x < y; });
+    for (int rank = 1; rank <= n; ++rank)
+    {
+        int x = ord[rank];
+        pos[x] = rank, pre[x] = (rank == 1 ? 0 : ord[rank - 1]), nxt[x] = (rank == n ? 0 : ord[rank + 1]);
+    }
+    int mid = ord[n / 2 + 1], cnt = 0;
+    for (int len = n; len >= 1; --len)
+    {
+        if (len & 1)
+            ans[++cnt] = a[mid];
+        if (len == 1)
+            break;
+        int x = len;
+        if (len & 1)
+        {
+            if (pos[x] <= pos[mid])
+                mid = nxt[mid];
+        }
+        else if (pos[x] >= pos[mid])
+            mid = pre[mid];
+        if (pre[x])
+            nxt[pre[x]] = nxt[x];
+        if (nxt[x])
+            pre[nxt[x]] = pre[x];
+    }
+    for (int i = cnt; i >= 1; --i)
+        printf("%d\n", ans[i]);
+    return 0;
+}