diff --git a/algorithm/sorting/bubble/basic/code.js b/algorithm/sorting/bubble/basic/code.js
index e48fd467..d445ca69 100644
--- a/algorithm/sorting/bubble/basic/code.js
+++ b/algorithm/sorting/bubble/basic/code.js
@@ -7,13 +7,13 @@ do {
     swapped = false;
     tracer._select(N - 1);
     for (var i = 1; i < N; i++) {
+        tracer._notify(i - 1, i);
         if (D[i - 1] > D[i]) {
             tracer._print('swap ' + D[i - 1] + ' and ' + D[i]);
             var temp = D[i - 1];
             D[i - 1] = D[i];
             D[i] = temp;
             swapped = true;
-            tracer._notify(i - 1, i);
         }
     }
     tracer._deselect(N - 1);
diff --git a/algorithm/sorting/quick/basic/code.js b/algorithm/sorting/quick/basic/code.js
index 84419726..781a4a9c 100644
--- a/algorithm/sorting/quick/basic/code.js
+++ b/algorithm/sorting/quick/basic/code.js
@@ -17,11 +17,11 @@ function partition(low, high) {
     var temp;
     
     for (var j = low; j < high; j++) {
+        tracer._notify(i, j);
         if (D[j] <= pivot) {
             temp = D[i];
             D[i] = D[j];
             D[j] = temp;
-            tracer._notify(i, j);
             i++;
         }
     }
diff --git a/algorithm/sorting/selection/basic/code.js b/algorithm/sorting/selection/basic/code.js
index efeefe59..d5b68323 100644
--- a/algorithm/sorting/selection/basic/code.js
+++ b/algorithm/sorting/selection/basic/code.js
@@ -5,11 +5,9 @@ for (var i = 0; i < D.length - 1; i++) {
     var minJ = i;
     tracer._select(i);
     for (var j = i + 1; j < D.length; j++) {
-        if (D[j] < D[minJ]) {
-            tracer._select(j);
-            minJ = j;
-            tracer._deselect(j);
-        }
+        tracer._select(j);
+        if (D[j] < D[minJ]) minJ = j;
+        tracer._deselect(j);
     }
     if (minJ != i) {
         tracer._print('swap ' + D[i] + ' and ' + D[minJ]);