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krotnamekrotname
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Deque
1 parent 8b1fa1d commit 57eb1f1

1 file changed

Lines changed: 155 additions & 156 deletions

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‎src/main/java/algorithms/sprint2/Deque.java‎

Lines changed: 155 additions & 156 deletions
Original file line numberDiff line numberDiff line change
@@ -44,132 +44,12 @@
4444
В этих случаях состояние (head, tail, size) не меняется, что сохраняет инварианты.
4545
4646
Сложность
47-
Каждая операция дека выполняет константное число действий: O(1) по времени.
47+
Время: O(n), где n - количество операций. Каждая операция дека выполняется за O(1)
4848
Память: массив из m элементов и несколько целых переменных: O(m) по памяти.
4949
*/
5050

51-
public class Deque {
52-
53-
// -------------------- FAST INPUT --------------------
54-
static final class FastIn {
55-
private final InputStream in;
56-
private final byte[] buf = new byte[1 << 16];
57-
private int ptr = 0, len = 0;
58-
59-
FastIn(InputStream in) {
60-
this.in = in;
61-
}
62-
63-
private int read() throws IOException {
64-
if (ptr >= len) {
65-
len = in.read(buf);
66-
ptr = 0;
67-
if (len <= 0) {
68-
return -1;
69-
}
70-
}
71-
return buf[ptr++];
72-
}
73-
74-
int nextInt() throws IOException {
75-
int c;
76-
do {
77-
c = read();
78-
if (c == -1) {
79-
throw new EOFException("Unexpected EOF");
80-
}
81-
} while (c <= ' ');
8251

83-
int sign = 1;
84-
if (c == '-') {
85-
sign = -1;
86-
c = read();
87-
}
88-
89-
int val = 0;
90-
while (c > ' ') {
91-
val = val * 10 + (c - '0');
92-
c = read();
93-
}
94-
return val * sign;
95-
}
96-
97-
String next() throws IOException {
98-
int c;
99-
do {
100-
c = read();
101-
if (c == -1) {
102-
throw new EOFException("Unexpected EOF");
103-
}
104-
} while (c <= ' ');
105-
106-
byte[] tmp = new byte[32];
107-
int n = 0;
108-
while (c > ' ') {
109-
if (n == tmp.length) {
110-
byte[] t2 = new byte[tmp.length * 2];
111-
System.arraycopy(tmp, 0, t2, 0, tmp.length);
112-
tmp = t2;
113-
}
114-
tmp[n++] = (byte) c;
115-
c = read();
116-
if (c == -1) {
117-
break;
118-
}
119-
}
120-
return new String(tmp, 0, n);
121-
}
122-
}
123-
124-
// -------------------- FAST OUTPUT --------------------
125-
static final class FastOut {
126-
private final OutputStream out;
127-
private final byte[] buf = new byte[1 << 16];
128-
private int p = 0;
129-
private final byte[] tmp = new byte[12];
130-
131-
FastOut(OutputStream out) {
132-
this.out = out;
133-
}
134-
135-
void writeByte(int b) throws IOException {
136-
if (p == buf.length) {
137-
flush();
138-
}
139-
buf[p++] = (byte) b;
140-
}
141-
142-
void writeStr(String s) throws IOException {
143-
for (int i = 0; i < s.length(); i++) {
144-
writeByte(s.charAt(i));
145-
}
146-
}
147-
148-
void writeInt(int x) throws IOException {
149-
if (x == 0) {
150-
writeByte('0');
151-
return;
152-
}
153-
if (x < 0) {
154-
writeByte('-');
155-
x = -x;
156-
}
157-
158-
int k = 0;
159-
while (x > 0) {
160-
tmp[k++] = (byte) ('0' + (x % 10));
161-
x /= 10;
162-
}
163-
for (int i = k - 1; i >= 0; i--) {
164-
writeByte(tmp[i]);
165-
}
166-
}
167-
168-
void flush() throws IOException {
169-
out.write(buf, 0, p);
170-
p = 0;
171-
}
172-
}
52+
public class Deque {
17353

17454
// -------------------- RING BUFFER DEQUE --------------------
17555
static final class RingDeque {
@@ -185,19 +65,11 @@ static final class RingDeque {
18565
}
18666

18767
private int next(int i) {
188-
i++;
189-
if (i == cap) {
190-
i = 0;
191-
}
192-
return i;
68+
return (i+1) % cap;
19369
}
19470

19571
private int prev(int i) {
196-
i--;
197-
if (i == -1) {
198-
i = cap - 1;
199-
}
200-
return i;
72+
return (i-1+cap) % cap;
20173
}
20274

20375
boolean isEmpty() {
@@ -244,33 +116,38 @@ private static void process(FastIn in, FastOut out) throws Exception {
244116
for (int i = 0; i < n; i++) {
245117
String cmd = in.next();
246118

247-
if ("push_back".equals(cmd)) {
248-
int x = in.nextInt();
249-
if (dq.isFull()) {
250-
out.writeStr("error\n");
251-
} else {
252-
dq.pushBack(x);
119+
switch (cmd) {
120+
case "push_back" -> {
121+
int x = in.nextInt();
122+
if (dq.isFull()) {
123+
out.writeStr("error\n");
124+
} else {
125+
dq.pushBack(x);
126+
}
253127
}
254-
} else if ("push_front".equals(cmd)) {
255-
int x = in.nextInt();
256-
if (dq.isFull()) {
257-
out.writeStr("error\n");
258-
} else {
259-
dq.pushFront(x);
128+
case "push_front" -> {
129+
int x = in.nextInt();
130+
if (dq.isFull()) {
131+
out.writeStr("error\n");
132+
} else {
133+
dq.pushFront(x);
134+
}
260135
}
261-
} else if ("pop_front".equals(cmd)) {
262-
if (dq.isEmpty()) {
263-
out.writeStr("error\n");
264-
} else {
265-
out.writeInt(dq.popFront());
266-
out.writeByte('\n');
136+
case "pop_front" -> {
137+
if (dq.isEmpty()) {
138+
out.writeStr("error\n");
139+
} else {
140+
out.writeInt(dq.popFront());
141+
out.writeByte('\n');
142+
}
267143
}
268-
} else { // pop_back
269-
if (dq.isEmpty()) {
270-
out.writeStr("error\n");
271-
} else {
272-
out.writeInt(dq.popBack());
273-
out.writeByte('\n');
144+
case "pop_back" -> {
145+
if (dq.isEmpty()) {
146+
out.writeStr("error\n");
147+
} else {
148+
out.writeInt(dq.popBack());
149+
out.writeByte('\n');
150+
}
274151
}
275152
}
276153
}
@@ -385,4 +262,126 @@ public static void main(String[] args) throws Exception {
385262
run();
386263
}
387264
}
265+
266+
// -------------------- FAST INPUT --------------------
267+
static final class FastIn {
268+
private final InputStream in;
269+
private final byte[] buf = new byte[1 << 16];
270+
private int ptr = 0, len = 0;
271+
272+
FastIn(InputStream in) {
273+
this.in = in;
274+
}
275+
276+
private int read() throws IOException {
277+
if (ptr >= len) {
278+
len = in.read(buf);
279+
ptr = 0;
280+
if (len <= 0) {
281+
return -1;
282+
}
283+
}
284+
return buf[ptr++];
285+
}
286+
287+
int nextInt() throws IOException {
288+
int c;
289+
do {
290+
c = read();
291+
if (c == -1) {
292+
throw new EOFException("Unexpected EOF");
293+
}
294+
} while (c <= ' ');
295+
296+
int sign = 1;
297+
if (c == '-') {
298+
sign = -1;
299+
c = read();
300+
}
301+
302+
int val = 0;
303+
while (c > ' ') {
304+
val = val * 10 + (c - '0');
305+
c = read();
306+
}
307+
return val * sign;
308+
}
309+
310+
String next() throws IOException {
311+
int c;
312+
do {
313+
c = read();
314+
if (c == -1) {
315+
throw new EOFException("Unexpected EOF");
316+
}
317+
} while (c <= ' ');
318+
319+
byte[] tmp = new byte[32];
320+
int n = 0;
321+
while (c > ' ') {
322+
if (n == tmp.length) {
323+
byte[] t2 = new byte[tmp.length * 2];
324+
System.arraycopy(tmp, 0, t2, 0, tmp.length);
325+
tmp = t2;
326+
}
327+
tmp[n++] = (byte) c;
328+
c = read();
329+
if (c == -1) {
330+
break;
331+
}
332+
}
333+
return new String(tmp, 0, n);
334+
}
335+
}
336+
337+
// -------------------- FAST OUTPUT --------------------
338+
static final class FastOut {
339+
private final OutputStream out;
340+
private final byte[] buf = new byte[1 << 16];
341+
private int p = 0;
342+
private final byte[] tmp = new byte[12];
343+
344+
FastOut(OutputStream out) {
345+
this.out = out;
346+
}
347+
348+
void writeByte(int b) throws IOException {
349+
if (p == buf.length) {
350+
flush();
351+
}
352+
buf[p++] = (byte) b;
353+
}
354+
355+
void writeStr(String s) throws IOException {
356+
for (int i = 0; i < s.length(); i++) {
357+
writeByte(s.charAt(i));
358+
}
359+
}
360+
361+
void writeInt(int x) throws IOException {
362+
if (x == 0) {
363+
writeByte('0');
364+
return;
365+
}
366+
if (x < 0) {
367+
writeByte('-');
368+
x = -x;
369+
}
370+
371+
int k = 0;
372+
while (x > 0) {
373+
tmp[k++] = (byte) ('0' + (x % 10));
374+
x /= 10;
375+
}
376+
for (int i = k - 1; i >= 0; i--) {
377+
writeByte(tmp[i]);
378+
}
379+
}
380+
381+
void flush() throws IOException {
382+
out.write(buf, 0, p);
383+
p = 0;
384+
}
385+
}
386+
388387
}

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