Create 1638A-Reverse.cpp

Author: DionysiosB

1638A-Reverse.cpp

@@ -0,0 +1,26 @@
+#include <cstdio>
+#include <vector>
+
+int main(){
+
+    long t; scanf("%ld", &t);
+    while(t--){
+        long n; scanf("%ld", &n);
+        std::vector<long> a(n + 1); long start(-1), stop(-1);
+        for(long p = 1; p <= n; p++){
+            scanf("%ld", &a[p]);
+            if(start < 0 &&  p != a[p]){start = p;}
+            else if(a[p] == start){stop = p;}
+        }
+
+        for(long p = 0; start > 0 && 2 * p <= stop - start; p++){
+            long tmp = a[start + p];
+            a[start + p] = a[stop - p];
+            a[stop - p] = tmp;
+        }
+
+        for(long p = 1; p <= n; p++){printf("%ld ", a[p]);}
+        puts("");
+    }
+
+}