ACM?java???

???????????? ???????[ 2014/2/8 10:46:34 ] ???????????? ???????

????3. ?????????
????java???????String??????????????????????????????.
?????????

import java.io.*;

import java.math.*;

import java.util.*;

import java.text.*;

public class Main

{

public static void main(String[] args)

{

int i;

Scanner cin = new Scanner (new BufferedInputStream(System.in));

String st = "abcdefg";

System.out.println(st.charAt(0)); // st.charAt(i)????st[i].

char [] ch;

ch = st.toCharArray(); // ????????????????.

for (i = 0; i < ch.length; i++) ch[i] += 1;

System.out.println(ch); // ?????“bcdefgh”.

if (st.startsWith("a")) // ??????????'0'???.

{

st = st.substring(1); // ????1λ???copy(??????0λ).

}

????4. ?????
????BigInteger??BigDecimal???????acmer???java????????
??????????add?? subtract?? divide?? mod?? compareTo??????м?????????????BigInteger(BigDecimal)??BigInteger(BigDecimal)?????????????????int(double)????????BigInteger(BigDecimal)???ú???BigInteger.valueOf().
?????????

import java.io.*;

import java.math.*;

import java.util.*;

import java.text.*;

public class Main

{

public static void main(String[] args)

{

Scanner cin = new Scanner (new BufferedInputStream(System.in));

int a = 123?? b = 456?? c = 7890;

BigInteger x?? y?? z?? ans;

x = BigInteger.valueOf(a); y = BigInteger.valueOf(b); z = BigInteger.valueOf(c);

ans = x.add(y); System.out.println(ans);

ans = z.divide(y); System.out.println(ans);

ans = x.mod(z); System.out.println(ans);

if (ans.compareTo(x) == 0) System.out.println("1");

}

????5. ???????
????java??????????????
??????????
????String st = Integer.toString(num?? base); // ??num????10??????????base?????st(base <= 35).
????int num = Integer.parseInt(st?? base); // ??st????base????????10?????int(parseInt??????????????????????????????????????????????).
????BigInter m = new BigInteger(st?? base); // st?????????base??st?????.
????6. ????
??????????Arrays.sort();?????????????壬??C++??д??cmp?????????java?????????????????????????
?????????

import java.io.*;

import java.math.*;

import java.util.*;

import java.text.*;

public class Main

{

public static void main(String[] args)

{

Scanner cin = new Scanner (new BufferedInputStream(System.in));

int n = cin.nextInt();

int a[] = new int [n];

for (int i = 0; i < n; i++) a[i] = cin.nextInt();