diff --git a/Correct.cpp b/Correct.cpp
index 6cbf30c..375773c 100644
--- a/Correct.cpp
+++ b/Correct.cpp
@@ -1804,10 +1804,13 @@ inline int move_gap_greedy(char* path, int path_i, int path_length, char* x, int
 inline void generate_cigar(char* path, int path_length, window_list *idx, window_list_alloc *res, int* start, int* end, unsigned int* old_error,
     char* x, int x_len, char* y)
 {
+    // uint8_t debug_c; uint32_t debug_c_len;
     idx->cidx = res->c.n;
     if ((*old_error) == 0) {
         push_cigar_cell(res, 0, idx->x_end + 1 - idx->x_start);
         idx->clen = res->c.n - idx->cidx;
+        // get_cigar_cell(idx, res, idx->clen-1, &debug_c, &debug_c_len);
+        // assert(debug_c==0 && debug_c_len==(idx->x_end + 1 - idx->x_start));
         return;
     }
 
@@ -1887,7 +1890,11 @@ inline void generate_cigar(char* path, int path_length, window_list *idx, window
     pre_c = 5; pre_cl = 0;
     for (i = path_length - 1; i >= 0; i--) {
         if (pre_c != path[i]) {
-            if (pre_cl != 0) push_cigar_cell(res, pre_c, pre_cl);
+            if (pre_cl != 0) {
+                push_cigar_cell(res, pre_c, pre_cl);
+                // get_cigar_cell(idx, res, res->c.n - idx->cidx - 1, &debug_c, &debug_c_len);
+                // assert(debug_c==pre_c && debug_c_len==pre_cl);
+            }
             pre_c = path[i]; pre_cl = 1;
         }
         else {
@@ -1895,7 +1902,12 @@ inline void generate_cigar(char* path, int path_length, window_list *idx, window
         }
     }
 
-    if (pre_cl != 0) push_cigar_cell(res, pre_c, pre_cl);    
+    if (pre_cl != 0) {
+        push_cigar_cell(res, pre_c, pre_cl);   
+        // get_cigar_cell(idx, res, res->c.n - idx->cidx -1, &debug_c, &debug_c_len);
+        // assert(debug_c==pre_c && debug_c_len==pre_cl);
+    }
+
     idx->clen = res->c.n - idx->cidx;
     // if(verify_cigar(x, x_len, y, (*end) - (*start) + 1, &(result->cigar), *old_error))
     // {
diff --git a/Correct.h b/Correct.h
index a3852c8..df6de7a 100644
--- a/Correct.h
+++ b/Correct.h
@@ -1251,14 +1251,14 @@ inline int if_exact_match(char* x, long long xLen, char* y, long long yLen, long
 
 inline void get_cigar_cell(window_list *idx, window_list_alloc *cc, uint32_t i, uint8_t *c, uint32_t *len)
 {
-    uint32_t p = cc->c.a[idx->cidx+i];
-    (*c) = (uint8_t)(p>>30); (*len) = (p<<2)>>2;
+    uint16_t p = cc->c.a[idx->cidx+i];
+    (*c) = (uint8_t)(p>>14); (*len) = (p&((uint16_t)0x3fff));
 }
 
 inline void push_cigar_cell(window_list_alloc *res, uint8_t c, uint32_t len)
 {
-    uint32_t p = c; p <<= 30; p += len;
-    kv_push(uint32_t, res->c, p);
+    uint16_t p = c; p <<= 14; p += (uint16_t)len;
+    kv_push(uint16_t, res->c, p);
 }
 
 #define FORWARD_KSW 0
diff --git a/Hash_Table.h b/Hash_Table.h
index 7677e3c..14c7409 100644
--- a/Hash_Table.h
+++ b/Hash_Table.h
@@ -44,29 +44,21 @@ typedef struct
     uint64_t end_pos;
 } k_mer_pos_list;
 
-// typedef struct
-// {
-//     int C_L[CIGAR_MAX_LENGTH];
-//     char C_C[CIGAR_MAX_LENGTH];
-//     int length;
-// } CIGAR;
-
 typedef struct
 {
   ///the begining and end of a window, instead of the whole overlap
   int32_t x_start, x_end;
   int32_t y_start, y_end;
-  int32_t extra_begin, extra_end;
-  int32_t error, error_threshold;
+  int16_t extra_begin, extra_end;
+  int16_t error, error_threshold;
   uint32_t cidx, clen;
-  //CIGAR cigar;
 } window_list;
 
 typedef struct
 {
     size_t n, m; 
     window_list *a;
-    kvec_t(uint32_t) c;
+    kvec_t(uint16_t) c;
 } window_list_alloc;
 
 typedef struct