import java.io.*;
import java.util.*;
/**
* Built using CHelper plug-in
* Actual solution is at the top
*/
public class polyline_av_n2 {
public static void main(String[] args) {
InputStream inputStream = System.in;
OutputStream outputStream = System.out;
FastScanner in = new FastScanner(inputStream);
PrintWriter out = new PrintWriter(outputStream);
Polyline solver = new Polyline();
solver.solve(1, in, out);
out.close();
}
static class Polyline {
public void solve(int testNumber, FastScanner in, PrintWriter out) {
int n = in.nextInt();
int MAX = 2000;
int INF = Integer.MAX_VALUE / 2;
int[] hasY = new int[MAX + 1];
Arrays.fill(hasY, INF);
hasY[0] = 0;
int lastX = -1;
for (int i = 0; i <n; i++) {
int x = in.nextInt();
hasY[x] = in.nextInt();
if (i + 1 == n) {
lastX = x;
}
}
int[][][] dp = new int[2][lastX + 1][2 * MAX + 1];
int[][][] pr = new int[2][lastX + 1][2 * MAX + 1];
for (int[][] i : dp) {
for (int[] j : i) {
Arrays.fill(j, INF);
}
}
dp[0][0][0 + MAX] = dp[1][0][0 + MAX] = 0;
for (int x = 0; x < lastX; x++) {
int startY = -MAX, endY = MAX;
if (hasY[x] != INF) {
startY = endY = hasY[x];
}
for (int y = startY; y <= endY; y++) {
for (int d = 0; d < 2; d++) {
int val = dp[d][x][y + MAX];
if (val != INF) {
for (int newD = 0; newD < 2; newD++) {
int newVal = val + ((d == newD) ? 0 : 1);
if (dp[newD][x + 1][y + MAX + (2 * newD - 1)] > newVal) {
dp[newD][x + 1][y + MAX + (2 * newD - 1)] = newVal;
pr[newD][x + 1][y + MAX + (2 * newD - 1)] = d;
}
}
}
}
}
}
int bestD = dp[0][lastX][hasY[lastX] + MAX] < dp[1][lastX][hasY[lastX] + MAX] ? 0 : 1;
if (dp[bestD][lastX][hasY[lastX] + MAX] == INF) {
out.println(-1);
} else {
List<Integer> ls = new ArrayList<>();
List<Character> cs = new ArrayList<>();
int curY = hasY[lastX], curD = bestD;
for (int curX = lastX; curX > 0; curX--) {
int prevD = pr[curD][curX][curY + MAX];
char c = curD == 1 ? '+' : '-';
if (cs.size() > 0 && cs.get(cs.size() - 1) == c) {
ls.set(ls.size() - 1, ls.get(ls.size() - 1) + 1);
} else {
ls.add(1);
cs.add(c);
}
curY -= 2 * curD - 1;
curD = prevD;
}
out.println(ls.size());
for (int i = ls.size() - 1; i >= 0; i--) {
out.println(ls.get(i) + " " + cs.get(i));
}
}
}
}
static class FastScanner {
public BufferedReader br;
public StringTokenizer st;
public FastScanner(InputStream in) {
br = new BufferedReader(new InputStreamReader(in));
}
public FastScanner(String fileName) {
try {
br = new BufferedReader(new FileReader(fileName));
} catch (FileNotFoundException e) {
e.printStackTrace();
}
}
public int nextInt() {
return Integer.parseInt(next());
}
public String next() {
while (st == null || !st.hasMoreElements()) {
String line = null;
try {
line = br.readLine();
} catch (IOException e) {
throw new UnknownError();
}
if (line == null) {
throw new UnknownError();
}
st = new StringTokenizer(line);
}
return st.nextToken();
}
}
}
Compilation message
Main.java:8: error: class polyline_av_n2 is public, should be declared in a file named polyline_av_n2.java
public class polyline_av_n2 {
^
1 error
