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xiaoningningxiaoningning
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update doc for basic data structure
1 parent 7220492 commit cd5a9e3

11 files changed

Lines changed: 52 additions & 132 deletions

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‎ActivityZero/src/ActivityZero.java‎

Lines changed: 2 additions & 7 deletions
Original file line numberDiff line numberDiff line change
@@ -3,12 +3,9 @@
33
import java.util.Scanner;
44

55
/**
6-
* User: ning wei
7-
* Date: 5/2/12
8-
* Time: 8:23 PM
9-
*
6+
*
107
* You'll be given a list of activities and their caloric impact.
11-
* Write a program that outputs the names of activities a Dropboxer should choose to partake in
8+
* Write a program that outputs the names of activities one should choose to partake in
129
* so that the sum of their caloric impact is zero.
1310
* Once an activity is selected, it cannot be chosen again.
1411
*
@@ -41,9 +38,7 @@ public static void main(String args[]) {
4138

4239
ActivityZero az = new ActivityZero(tempArray[0], Integer.parseInt(tempArray[1]));
4340
listActivityZero.add(az);
44-
4541
n--;
46-
4742
}
4843

4944
scanner.close();

‎IntArrayOps/src/IntArrayOps.java‎

Lines changed: 28 additions & 44 deletions
Original file line numberDiff line numberDiff line change
@@ -12,7 +12,6 @@ public static void main(String[] args) {
1212
a[i] = 0 + (int) (Math.random() * length);
1313
}
1414

15-
1615
System.out.println(Arrays.toString(a));
1716

1817
int[] a1 = new int[]{7, 8, 9, 10, 13, 0, 1, 2, 0, 9, 13, 14};
@@ -45,12 +44,12 @@ public static void main(String[] args) {
4544
System.out.println("a1 rank " + rank + " : " + pick);
4645

4746
int a3 = 134;
48-
System.out.println(a3 + " reversed to " + reverseInt(a3));
47+
System.out.println(a3 + " reversed to " + isPalindrome1(a3));
4948

5049
int a4 = 1551;
5150
System.out.println(a4 + " isPalindrome: " + isPalindrome(a4));
5251

53-
int[] a5 = new int[]{3, 5, 10, -1, 1};
52+
int[] a5 = new int[]{3, -1, 1, 2, 4};
5453

5554
System.out.println(Arrays.toString(a5) + " 1st missing positiv: " + firstMissingPositive(a5, a5.length));
5655

@@ -63,7 +62,7 @@ public static void main(String[] args) {
6362
removeDupInplace(a8);
6463
System.out.println("remove dup of a sorted arr in place: " + Arrays.toString(a8));
6564

66-
int[] a9 = new int[]{-1, -1, 1, 1, 2, 2, 3, 4, 4, 5, 6, 6, 7,7,8};
65+
int[] a9 = new int[]{-1, -1, 1, 1, 2, 2, 3, 4, 4, 5, 6, 6, 7, 7, 8};
6766
removeDupInplace2(a9);
6867
System.out.println("remove dup of a sorted arr in place2: " + Arrays.toString(a9));
6968

@@ -193,7 +192,6 @@ public static void removeDupInplace1(int[] a) {
193192
if (a[j] != a[i]) {
194193
a[j + 1] = a[i];
195194
j++;
196-
197195
}
198196
}
199197
j++;
@@ -203,6 +201,7 @@ public static void removeDupInplace1(int[] a) {
203201
}
204202
}
205203

204+
// not a good solution
206205
public static void removeDupInplace(int[] a) {
207206
if (a.length <= 1) return;
208207

@@ -230,8 +229,6 @@ public static void removeDupInplace(int[] a) {
230229
}
231230
if (a[i] == 0)
232231
return;
233-
234-
235232
}
236233

237234
}
@@ -252,14 +249,9 @@ public static void mergeSorted(int[] l, int[] s) {
252249
while (k >= 0) {
253250
if (s[k] >= l[j]) {
254251
l[i--] = s[k--];
255-
//i--;
256-
//k--;
257252
} else {
258253
l[i--] = l[j--];
259-
//i--;
260-
//j--;
261254
}
262-
263255
}
264256

265257
while (k >= 0) {
@@ -268,16 +260,17 @@ public static void mergeSorted(int[] l, int[] s) {
268260
}
269261

270262
public static int firstMissingPositive(int A[], int n) {
263+
264+
if (A.length == 0) return 1;
265+
271266
//The key idea is to put every element in A such that A[i]=i+1
272267
for (int i = 0; i < n; i++) {
273-
//System.out.println(Arrays.toString(A));
274268
while (A[i] != i + 1 && A[i] > 0 && A[i] <= n && A[i] != A[A[i] - 1]) {
275269
int temp = A[i];
276270
A[i] = A[temp - 1];
277271
A[temp - 1] = temp;
278272
}
279273
}
280-
//System.out.println(Arrays.toString(A));
281274
for (int i = 0; i < n; i++) {
282275
if (A[i] != i + 1) return i + 1;
283276
}
@@ -300,6 +293,11 @@ public static boolean isPalindrome(int x) {
300293
return true;
301294
}
302295

296+
public static boolean isPalindrome1(int x) {
297+
if (x < 0) return false;
298+
return x == reverseInt(x);
299+
}
300+
303301
public static int reverseInt(int a) {
304302
int r = 0;
305303
while (a != 0) {
@@ -313,54 +311,47 @@ public static int reverseInt(int a) {
313311
// longest increasing sequence
314312
public static ArrayList<Integer> LIS(int[] a) {
315313

316-
LinkedList<Integer> memo = new LinkedList<Integer>();
314+
LinkedList<Integer> trackLargestIndex = new LinkedList<Integer>();
317315
int[] path = new int[a.length];
318316

319-
memo.add(0);
317+
trackLargestIndex.add(0);
320318
path[0] = 0;
321319

322320
for (int i = 1; i < a.length; ++i) {
323321

324-
if (a[memo.getLast()] <= a[i]) {
325-
path[i] = memo.getLast(); // record the index of previous smaller element
326-
memo.add(i); // record the index of the largest element
322+
if (a[trackLargestIndex.getLast()] <= a[i]) {
323+
path[i] = trackLargestIndex.getLast(); // record the index of previous smaller element
324+
trackLargestIndex.add(i); // record the index of the largest element
327325
} else {
328326
int s, e;
329-
for (s = 0, e = memo.size() - 1; s < e; ) {
327+
for (s = 0, e = trackLargestIndex.size() - 1; s < e; ) {
330328

331329
int m = (e + s) / 2;
332330

333-
if (a[memo.get(m)] <= a[i])
331+
if (a[trackLargestIndex.get(m)] <= a[i])
334332
s = m + 1;
335333
else
336334
e = m;
337335

338336
}
339-
if (a[i] < a[memo.get(s)]) {
340-
memo.set(s, i);
337+
if (a[i] < a[trackLargestIndex.get(s)]) {
338+
trackLargestIndex.set(s, i);
341339
if (s > 0)
342-
path[i] = memo.get(s - 1);
340+
path[i] = trackLargestIndex.get(s - 1);
343341
else
344342
path[i] = 0;
345343
}
346-
347344
}
348-
349345
}
350346

351-
int pos = memo.getLast();
347+
int index = trackLargestIndex.getLast();
352348
ArrayList<Integer> lis = new ArrayList<Integer>();
353-
for (int n = 0; n < memo.size(); ++n) {
354-
lis.add(0, a[pos]);
355-
pos = path[pos];
349+
for (int n = 0; n < trackLargestIndex.size(); ++n) {
350+
lis.add(0, a[index]);
351+
index = path[index];
356352
}
357353

358-
// System.out.println("LIS: " + lis.toString());
359-
// reverse the order
360-
Collections.sort(lis);
361-
362354
return lis;
363-
364355
}
365356

366357
public static int LIS1(int[] a) {
@@ -390,9 +381,7 @@ else if (a[i] >= a[trackTable[max]]) {
390381
}
391382

392383
}
393-
//System.out.println(Arrays.toString(trackTable));
394384
return max;
395-
396385
}
397386

398387
public static int partition(int[] a, int left, int right) {
@@ -402,17 +391,17 @@ public static int partition(int[] a, int left, int right) {
402391
right--;
403392
while (a[left] < pivot)
404393
left++;
394+
405395
if (left <= right) {
406396
int tmp = a[right];
407397
a[right] = a[left];
408398
a[left] = tmp;
399+
409400
right--;
410401
left++;
411402
}
412403

413404
}
414-
// System.out.print(pivot + " : " );
415-
// System.out.println(Arrays.toString(a));
416405
return left;
417406
}
418407

@@ -439,7 +428,6 @@ public static int pickRank(int[] a, int left, int right, int rank) {
439428
if (leftSize == rank)
440429
return max(a, left, pivotIndex);
441430
else if (rank < leftSize) {
442-
// System.out.println(left +" "+ pivotIndex + " " + rank );
443431
return pickRank(a, left, pivotIndex - 1, rank);
444432
} else //(rank > leftSize)
445433
return pickRank(a, pivotIndex, right, rank - leftSize);
@@ -456,7 +444,6 @@ public static void mergeSort(int[] a, int s, int e) {
456444

457445
public static void merge(int[] a, int left, int middle, int right) {
458446

459-
// int[] helper = a.clone();
460447
int[] helper = new int[a.length];
461448

462449
for (int i = left; i <= right; ++i) {
@@ -475,9 +462,7 @@ public static void merge(int[] a, int left, int middle, int right) {
475462
a[current] = helper[helperMiddle];
476463
helperMiddle--;
477464
current--;
478-
479465
}
480-
481466
}
482467

483468
while (helperRight > middle) {
@@ -488,5 +473,4 @@ public static void merge(int[] a, int left, int middle, int right) {
488473

489474
}
490475

491-
492476
}

‎LRU/src/LRUCache.java‎

Lines changed: 0 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -40,7 +40,6 @@ public boolean remove(K key) {
4040
return true;
4141
} else
4242
return false;
43-
4443
}
4544

4645
public int size() {
@@ -56,7 +55,6 @@ public V get(K key) {
5655
public V getFirst(){
5756
if(!queue.isEmpty()){
5857
return lru.get(queue.peek());
59-
6058
}
6159
else
6260
return null;

‎PuzzleCoding/src/LongestBalanceSubstring.java‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -26,7 +26,7 @@ public static void main(String[] args) {
2626
String balanceString = longestBalanceSubstring(s);
2727
System.out.println(balanceString);
2828

29-
String s1 = "0101001";
29+
String s1 = "11010";
3030
String balanceString1 = longestBalanceSubstring(s1);
3131
System.out.println(balanceString1);
3232

‎PuzzleCoding/src/LongestStringWithoutRepeat.java‎

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -36,6 +36,7 @@ public static String longestStringWithoutRepeat(String s) {
3636
}
3737
}
3838

39+
// the last case a[n-1] is not repeated
3940
if (n - start > maxLen) {
4041
maxLen = n - start;
4142
maxStart = start;

‎PuzzleCoding/src/MergeSortedArray.java‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -70,7 +70,7 @@ private void shiftDown(int k) {
7070
int j = i + 1; //right
7171
//find the smallest of left and right
7272
if (i < heap.size() - 1 && greater(i, j)) {
73-
i++;
73+
i++; // i = j;
7474
}
7575
if (greater(i, k)) break;
7676
swap(i, k);

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