Solved, yay I'm happy. I had to put this aside for a couple of monthsHEADmaster

due to busy work and family life. Yesterday and today I got a little
time so I fired up IDEA and started hacking at this again.

Lesson learned/reinforced: don't give up, don't dismiss small steps,
take those steps like a marathon, and you'll inch closer and finally
reach the destination! I found that it helped me that I wrote down
those little steps, started them, finished them, and closed them one
by one. This gave me momentum to carry it through! Pretty happy about
it.

1 files changed, 30 insertions, 19 deletions

diff --git a/src/main/SetRangeSum.java b/src/main/SetRangeSum.java
index 8c75189..0d01382 100644
--- a/src/main/SetRangeSum.java
+++ b/src/main/SetRangeSum.java
@@ -8,6 +8,7 @@ public class SetRangeSum {
     StringTokenizer st;
     boolean eof;
 
+    //    int last_sum_result = 0;
     long last_sum_result = 0;
     // Splay tree implementation
 
@@ -190,47 +191,57 @@ public class SetRangeSum {
     }
 
     void erase(int x) {
-        // Implement erase yourself
+        if (find(x)) {
+            root = merge(root.left, root.right);
+            if (root != null)
+                root.parent = null;
+            return;
+        }
+    }
+
+    boolean find(int x) {
+        if (root != null && root.key == x) return true;
         Vertex left = null;
         Vertex right = null;
-        Vertex new_vertex = null;
         VertexPair leftRight = split(root, x);
         left = leftRight.left;
         right = leftRight.right;
-
-        if (right == null) return;
-
-        new_vertex = right.right;
-        root = merge(left, new_vertex);
-
-    }
-
-    boolean find(int x) {
-        // Implement find yourself
-        VertexPair vertexPair = find(root, x);
-        if (vertexPair.left == null) return false;
-        if (vertexPair.left.key == x)
-            return true;
-        else return false;
+        if (right == null || right.key != x) {
+            root = merge(left, right);
+            if (right == null)
+                root = splay(left);
+            else
+                root = splay(right);
+            return false;
+        }
+        root = merge(left, right);
+        root = splay(right);
+        return true;
     }
 
     long sum(int from, int to) {
+        long ans = 0;
         VertexPair leftMiddle = split(root, from);
         Vertex left = leftMiddle.left;
         Vertex middle = leftMiddle.right;
         VertexPair middleRight = split(middle, to + 1);
         middle = middleRight.left;
         Vertex right = middleRight.right;
-        long ans = 0;
         if (left != null && left.key >= from && left.key <= to)
             ans = ans + left.sum;
+//        ans = ans + left.key;
+//        if (middle != null)
         if (middle != null && middle.key >= from && middle.key <= to)
             ans = ans + middle.sum;
         if (right != null && right.key >= from && right.key <= to)
             ans = ans + right.sum;
+//        ans = ans + right.key;
+        root = merge(merge(left, middle), right);
+//        last_sum_result = (int) (ans % MODULO);
         last_sum_result = ans;
 
         return ans;
+//        return last_sum_result;
     }
 
 
@@ -261,7 +272,7 @@ public class SetRangeSum {
                     int r = nextInt();
                     long res = sum((int) (l + last_sum_result) % MODULO, (int) (r + last_sum_result) % MODULO);
                     out.println(res);
-                    last_sum_result = (res % MODULO);
+                    last_sum_result = (int) (res % MODULO);
                 }
             }
         }