diff --git a/src/hstr.c b/src/hstr.c
index ee0a8ea..c1beee4 100644
--- a/src/hstr.c
+++ b/src/hstr.c
@@ -52,7 +52,7 @@
 #endif
 
 static char **selection=NULL;
-static int selectionSize=0;
+static unsigned selectionSize=0;
 static bool terminalHasColors=FALSE;
 
 
@@ -80,7 +80,7 @@ void print_history_label(WINDOW *win) {
 
 	strcpy(message, LABEL_HISTORY);
 	width -= strlen(LABEL_HISTORY);
-	int i;
+	unsigned i;
 	for (i=0; i < width; i++) {
 		strcat(message, " ");
 	}
@@ -92,12 +92,12 @@ void print_history_label(WINDOW *win) {
 	refresh();
 }
 
-int get_max_history_items(WINDOW *win) {
+unsigned get_max_history_items(WINDOW *win) {
 	return (getmaxy(win)-(Y_OFFSET_ITEMS+2));
 }
 
 
-void alloc_selection(int size) {
+void alloc_selection(unsigned size) {
 	selectionSize=size;
 	if(selection!=NULL) {
 		free(selection);
@@ -108,9 +108,9 @@ void alloc_selection(int size) {
 	}
 }
 
-int make_selection(char *prefix, HistoryItems *history, int maxSelectionCount) {
+unsigned make_selection(char *prefix, HistoryItems *history, int maxSelectionCount) {
 	alloc_selection(sizeof(char*) * maxSelectionCount); // TODO realloc
-	int i, selectionCount=0;
+	unsigned i, selectionCount=0;
 
     HashSet set;
     hashset_init(&set);
@@ -145,15 +145,15 @@ int make_selection(char *prefix, HistoryItems *history, int maxSelectionCount) {
 	return selectionCount;
 }
 
-char *print_selection(WINDOW *win, int maxHistoryItems, char *prefix, HistoryItems *history) {
+char *print_selection(WINDOW *win, unsigned maxHistoryItems, char *prefix, HistoryItems *history) {
 	char *result="";
-	int selectionCount=make_selection(prefix, history, maxHistoryItems);
+	unsigned selectionCount=make_selection(prefix, history, maxHistoryItems);
 	if (selectionCount > 0) {
 		result = selection[0];
 	}
 
 	int height=get_max_history_items(win);
-	int i;
+	unsigned i;
 	int y=Y_OFFSET_ITEMS;
 
 	move(Y_OFFSET_ITEMS, 0);
@@ -245,7 +245,6 @@ char *selection_loop(HistoryItems *history) {
 			break;
 		case 91:
 			// TODO 91 killed > debug to determine how to distinguish \e and [
-	        //mvprintw(Y_OFFSET_HELP, 0, "91 killed");
 			break;
 		case KEY_BACKSPACE:
 		case 127:
diff --git a/src/hstr_history.c b/src/hstr_history.c
index 7253c22..c6baa03 100644
--- a/src/hstr_history.c
+++ b/src/hstr_history.c
@@ -1,4 +1,12 @@
 #include "include/hstr_history.h"
+#include "include/hashset.h"
+#include "include/hashmap.h"
+#include "include/radixsort.h"
+
+typedef struct {
+	char *item;
+	unsigned rank;
+} RankedHistoryItem;
 
 static HistoryItems *history;
 static HistoryItems *prioritizedHistory;
@@ -13,16 +21,90 @@ char *get_history_file() {
 	return fileName;
 }
 
+#define history_ranking_function(RANK, NEWORDEROCCURENCE) (RANK?RANK+NEWORDEROCCURENCE:NEWORDEROCCURENCE)
+
+void dump_prioritized_history(HistoryItems *ph) {
+	printf("\n\nPrioritized history:");
+	int i;
+	for(i=0; i<ph->count; i++) {
+		if(ph->items[i]!=NULL) {
+			printf("\n%s",ph->items[i]); fflush(stdout);
+		} else {
+			printf("\n %d NULL",i); fflush(stdout);
+		}
+	}
+	printf("\n"); fflush(stdout);
+}
+
 HistoryItems *prioritize_history(HistoryItems *historyFileItems) {
-	return historyFileItems;
+	HashMap rankmap;
+	hashmap_init(&rankmap);
+
+	HashSet blacklist;
+	hashset_init(&blacklist);
+	hashset_add(&blacklist, "ls");
+	hashset_add(&blacklist, "pwd");
+	hashset_add(&blacklist, "cd");
+	hashset_add(&blacklist, "hh");
+
+	RadixSorter rs;
+	radixsort_init(&rs);
+
+	RankedHistoryItem *r;
+	RadixItem *radixItem;
+	int i;
+	for(i=0; i<historyFileItems->count; i++) {
+		if(hashset_contains(&blacklist, historyFileItems->items[i])) {
+			continue;
+		}
+		if((r=hashmap_get(&rankmap, historyFileItems->items[i]))==NULL) {
+			r=(RankedHistoryItem *)malloc(sizeof(RankedHistoryItem));
+			r->rank=history_ranking_function(0, i);
+			r->item=historyFileItems->items[i];
+
+			hashmap_put(&rankmap, historyFileItems->items[i], r);
+
+			radixItem=(RadixItem *)malloc(sizeof(RadixItem));
+			radixItem->key=r->rank;
+			radixItem->data=r;
+			radixItem->next=NULL;
+			radixsort_add(&rs, radixItem);
+		} else {
+			//printf("\n>>> %s ", r->item); fflush(stdout);
+			radixItem=radix_cut(&rs, r->rank, r);
+
+			if(radixItem!=NULL) {
+				r->rank=history_ranking_function(r->rank, i);
+				radixItem->key=r->rank;
+				radixsort_add(&rs, radixItem);
+			} // TODO else assert
+		}
+	}
+
+	RadixItem **prioritizedRadix=radixsort_dump(&rs);
+	prioritizedHistory=(HistoryItems *)malloc(sizeof(HistoryItems));
+	prioritizedHistory->count=rs.size;
+	prioritizedHistory->items=malloc(rs.size * sizeof(char*));
+	for(i=0; i<rs.size; i++) {
+		printf("\n %d %p ",i,prioritizedRadix[i]->data);
+		if(prioritizedRadix[i]->data) {
+			prioritizedHistory->items[i]=((RankedHistoryItem *)(prioritizedRadix[i]->data))->item;
+		}
+		printf("\n %d %s ",i,((RankedHistoryItem *)(prioritizedRadix[i]->data))->item);
+	}
+
+	radixsort_destroy(&rs);
+
+	return prioritizedHistory;
 }
 
 void free_prioritized_history() {
-	//free(prioritizedHistory->items);
-	//free(prioritizedHistory);
+	// TODO free(prioritizedHistory->items);
+	// TODO free(prioritizedHistory);
 }
 
 
+
 #ifdef GET_HISTORY_FROM_FILE
 
 static char *historyAsString;
diff --git a/src/hstr_utils.c b/src/hstr_utils.c
index 527dbbe..650f161 100644
--- a/src/hstr_utils.c
+++ b/src/hstr_utils.c
@@ -12,7 +12,7 @@ void tiocsti() {
 
 void fill_terminal_input(char *cmd){
 	size_t size = strlen(cmd);
-	int i;
+	unsigned i;
 	char *c;
 	for (i = 0; i < size; i++) {
 		// terminal I/O control, simulate terminal input
@@ -22,9 +22,9 @@ void fill_terminal_input(char *cmd){
 	printf("\n");
 }
 
-void reverse_char_pointer_array(char **array, int length) {
-	int i;
+void reverse_char_pointer_array(char **array, unsigned length) {
 	char *temp;
+	unsigned i;
     for (i=0; i<length/2; i++) {
         temp = array[i];
         array[i] = array[length-i-1];
diff --git a/src/include/hashset.h b/src/include/hashset.h
index e938b29..7df422b 100644
--- a/src/include/hashset.h
+++ b/src/include/hashset.h
@@ -12,18 +12,16 @@ struct HashNode {
     struct HashNode *next;
 };
 
-struct HashSetStruct {
+typedef struct {
     struct HashNode * lists[TABLE_SIZE];
     int currentSize;
-};
+} HashSet;
 
-typedef struct HashSetStruct HashSet;
-
-void hashset_init( HashSet * hs );
-int hashset_contains( const HashSet * hs, const char *key );
-int hashset_add( HashSet * hs, const char *key );
-int hashset_remove( HashSet * hs, const char *key );
-int hashset_size( const HashSet * hs );
-void hashset_print( const HashSet * hs );
+void hashset_init( HashSet *hs );
+int hashset_contains( const HashSet *hs, const char *key );
+int hashset_add( HashSet *hs, const char *key );
+int hashset_remove( HashSet *hs, const char *key );
+int hashset_size( const HashSet *hs );
+void hashset_print( const HashSet *hs );
 
 #endif
diff --git a/src/include/hstr_history.h b/src/include/hstr_history.h
index 9fa3540..617aeb3 100644
--- a/src/include/hstr_history.h
+++ b/src/include/hstr_history.h
@@ -20,7 +20,7 @@
 
 typedef struct {
 	char **items;
-	int count;
+	unsigned count;
 } HistoryItems;
 
 HistoryItems *get_history_items();
diff --git a/src/include/hstr_utils.h b/src/include/hstr_utils.h
index e8a9c53..2828c79 100644
--- a/src/include/hstr_utils.h
+++ b/src/include/hstr_utils.h
@@ -8,6 +8,6 @@
 
 void tiocsti();
 void fill_terminal_input(char* cmd);
-void reverse_char_pointer_array(char **array, int length);
+void reverse_char_pointer_array(char **array, unsigned length);
 
 #endif