Solved ARRAYSUB. Sliding window maximum.

ARRAYSUB/input.in

@@ -0,0 +1,3 @@
+9
+1  2  3  1  4  5  2  3  6
+2

ARRAYSUB/input2.in

@@ -0,0 +1,4 @@
+10
+
+10 9 4 7 8 5 4 3 2 1
+5

ARRAYSUB/source.cpp

@@ -0,0 +1,41 @@
+#include <cstdio>
+#include <queue>
+#include <utility>
+
+const int max_n = 1000010;
+int num[max_n];
+
+int main() {
+  int n;
+  scanf("%d", &n);
+
+  for(int i = 0; i < n; ++i) {
+    scanf("%d", &num[i]);
+  }
+
+  int k;
+  scanf("%d", &k);
+
+  bool first_case = true;
+  std::deque<int> q;
+  for(int i = 0; i < n; ++i) {
+    if(i >= k) {
+      if(!q.empty() && q.front() <= i - k) {
+        q.pop_front();
+      }
+    }
+    while(!q.empty() && num[i] >= num[q.back()]) {
+      q.pop_back();
+    }
+    q.push_back(i);
+    if(i >= k - 1) {
+      if(!first_case) {
+        printf(" ");
+      } else {
+        first_case = false;
+      }
+      printf("%d", num[q.front()]);
+    }
+  }
+  printf("\n");
+}