Update byot.html

byot.html

@@ -91,6 +91,7 @@ <h1>Build your own treap!</h1>
     <label><input type="checkbox" id="size_option"> Include size</label><br>
     <label><input type="checkbox" id="spliti_option"> Include split by index</label><br>
     <label><input type="checkbox" id="three_spliti_option"> Include 3-way split by index</label><br>
+    <label><input type="checkbox" id="findi_option"> Include find by index</label><br>
     <label><input type="checkbox" id="insi_option"> Include point insert by index</label><br>
     <label><input type="checkbox" id="deli_option"> Include point deletion by index</label><br>
 </div>
@@ -189,6 +190,7 @@ <h1>Build your own treap!</h1>
     let del_option = false;
     let size_option = false;
     let spliti_option = false;
+    let findi_option = false;
     let three_spliti_option = false;
     let insi_option = false;
     let deli_option = false;
@@ -233,6 +235,7 @@ <h1>Build your own treap!</h1>
         ["ins_option", "split_option"],
         ["spliti_option", "size_option"],
         ["insi_option", "spliti_option"],
+        ["findi_option", "size_option"],
         ["range_add", "lazy_prop"],
         ["range_set", "lazy_prop"],
         ["key_add", "lazy_prop"],
@@ -401,6 +404,7 @@ <h1>Build your own treap!</h1>
         split_option = document.getElementById("split_option").checked;
         three_split_option = document.getElementById("three_split_option").checked;
         find_option = document.getElementById("find_option").checked;
+        findi_option = document.getElementById("findi_option").checked;
         ins_option = document.getElementById("ins_option").checked;
         del_option = document.getElementById("del_option").checked;
         size_option = document.getElementById("size_option").checked;
@@ -743,14 +747,25 @@ <h1>Build your own treap!</h1>
         }
 
         if (find_option) {
-            code += `bool find(ptr n, ${key_type} k) {\n` +
-                '    if (!n) return false;\n' +
-                '    if (n->key == k) return true;\n' +
+            code += 'ptr find(ptr n, int k) {\n' +
+                '    if (!n) return 0;\n'
+            if (push) code += '    push(n);\n';
+            code += '    if (n->key == k) return n;\n' +
                 '    if (k <= n->key) return find(n->l, k);\n' +
                 '    else return find(n->r, k);\n' +
                 '}\n\n'
         }
 
+        if (findi_option) {
+            code += 'ptr findi(ptr n, int i) {\n' +
+                '    if (!n) return 0;\n'
+            if (push) code += '    push(n);\n'
+            code += '    if (sz(n->l) == i) return n;\n' +
+                '    if (i < sz(n->l)) return findi(n->l, i);\n' +
+                '    else return findi(n->r, i - sz(n->l) - 1);\n' +
+                '}\n\n'
+        }
+
         if (ins_option) {
             if (comments) code += '// returns root of new treap. only insert single nodes\n'
             code += 'ptr ins(ptr n, ptr it) {\n' +