結果

問題 No.742 にゃんにゃんにゃん 猫の挨拶
ユーザー tutuztutuz
提出日時 2018-10-06 18:25:23
言語 Java
(openjdk 23)
結果
AC  
実行時間 142 ms / 2,500 ms
コード長 3,538 bytes
コンパイル時間 2,325 ms
コンパイル使用メモリ 78,132 KB
実行使用メモリ 42,928 KB
最終ジャッジ日時 2024-10-12 14:04:44
合計ジャッジ時間 4,048 ms
ジャッジサーバーID
(参考情報)
judge5 / judge1
このコードへのチャレンジ
(要ログイン)
ファイルパターン 結果
other AC * 16
権限があれば一括ダウンロードができます

ソースコード

diff #
プレゼンテーションモードにする

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.InputMismatchException;
import java.util.StringTokenizer;
public class Main {
public static void main(String[] args) throws IOException {
InputStream inputStream = System.in;
OutputStream outputStream = System.out;
InputReader in = new InputReader(inputStream);
PrintWriter out = new PrintWriter(outputStream);
TaskX solver = new TaskX();
solver.solve(1, in, out);
out.close();
}
static int INF = 1 << 30;
static long LINF = 1L << 55;
static int MOD = 1000000007;
static int[] mh4 = { 0, -1, 1, 0 };
static int[] mw4 = { -1, 0, 0, 1 };
static int[] mh8 = { -1, -1, -1, 0, 0, 1, 1, 1 };
static int[] mw8 = { -1, 0, 1, -1, 1, -1, 0, 1 };
static class TaskX {
public void solve(int testNumber, InputReader in, PrintWriter out) {
int n = in.nextInt();
int[] a = in.nextIntArrayDec(n);
int ans = 0;
BIT bit = new BIT(n);
for (int i = 0; i < n; i++) {
ans += i - bit.query(a[i]);
bit.add(a[i], 1);
}
out.println(ans);
}
}
/**
* 0-indexed BinaryIndexTree
* */
static class BIT {
private int n;
private long[] bit;
public BIT(int n) {
this.n = n;
bit = new long[n + 1];
}
public void clear() {
Arrays.fill(bit, 0);
}
public void add(int i, long x) {
while (i <= n) {
bit[i] += x;
i |= i + 1;
}
}
public long query(int l, int r) {
return l <= r ? query(r) - query(l - 1) : 0;
}
private long query(int i) {
long s = 0;
while (i >= 0) {
s += bit[i];
i = (i & (i + 1)) - 1;
}
return s;
}
}
static class InputReader {
BufferedReader in;
StringTokenizer tok;
public String nextString() {
while (!tok.hasMoreTokens()) {
try {
tok = new StringTokenizer(in.readLine(), " ");
} catch (IOException e) {
throw new InputMismatchException();
}
}
return tok.nextToken();
}
public int nextInt() {
return Integer.parseInt(nextString());
}
public long nextLong() {
return Long.parseLong(nextString());
}
public double nextDouble() {
return Double.parseDouble(nextString());
}
public int[] nextIntArray(int n) {
int[] res = new int[n];
for (int i = 0; i < n; i++) {
res[i] = nextInt();
}
return res;
}
public int[] nextIntArrayDec(int n) {
int[] res = new int[n];
for (int i = 0; i < n; i++) {
res[i] = nextInt() - 1;
}
return res;
}
public int[] nextIntArray1Index(int n) {
int[] res = new int[n + 1];
for (int i = 0; i < n; i++) {
res[i + 1] = nextInt();
}
return res;
}
public long[] nextLongArray(int n) {
long[] res = new long[n];
for (int i = 0; i < n; i++) {
res[i] = nextLong();
}
return res;
}
public long[] nextLongArrayDec(int n) {
long[] res = new long[n];
for (int i = 0; i < n; i++) {
res[i] = nextLong() - 1;
}
return res;
}
public long[] nextLongArray1Index(int n) {
long[] res = new long[n + 1];
for (int i = 0; i < n; i++) {
res[i + 1] = nextLong();
}
return res;
}
public double[] nextDoubleArray(int n) {
double[] res = new double[n];
for (int i = 0; i < n; i++) {
res[i] = nextDouble();
}
return res;
}
public InputReader(InputStream inputStream) {
in = new BufferedReader(new InputStreamReader(inputStream));
tok = new StringTokenizer("");
}
}
}
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