diff --git "a/2-\346\225\260\345\255\246.md" "b/2-\346\225\260\345\255\246.md"
index ea9b4ee..0684f84 100644
--- "a/2-\346\225\260\345\255\246.md"
+++ "b/2-\346\225\260\345\255\246.md"
@@ -607,6 +607,17 @@ void rXOR(LL& a, LL& b) {
 }
 ```
 
++ FWT 子集卷积
+
+```text
+a[popcount(x)][x] = A[x]
+b[popcount(x)][x] = B[x]
+fwt(a[i]) fwt(b[i])
+c[i + j][x] += a[i][x] * b[j][x]
+rfwt(c[i])
+ans[x] = c[popcount(x)][x]
+```
+
 ## simpson 自适应积分
 
 ```cpp
diff --git a/template.pdf b/template.pdf
index b184b7b..9e3712d 100644
Binary files a/template.pdf and b/template.pdf differ