54 lines
1.4 KiB
Java
54 lines
1.4 KiB
Java
package com.thinker.bishi.saima;
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import java.util.Scanner;
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/**
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* @author lzh
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* <p href="http://exercise.acmcoder.com/online/online_judge_ques?ques_id=1656&konwledgeId=134">
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* http://exercise.acmcoder.com/online/online_judge_ques?ques_id=1656&konwledgeId=134
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* </p>
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*/
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public class OverTurnArray {
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public static void main(String[] args) {
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Scanner in = new Scanner(System.in);
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int len = in.nextInt();
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int[] arr = new int[len];
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for(int i=0;i<len;i++){
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arr[i] = in.nextInt();
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}
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getOverturn(arr,len);
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}
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private static void getOverturn(int[] arr,int len){
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int begin = 0,end = 0;
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boolean flag = false;
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//find begin and end
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for(int i=0;i<len-1;i++){
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if(!flag && arr[i] > arr[i+1]){
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begin = i;flag = true;
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}else if(flag && arr[i] < arr[i+1]){
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end = i;break;
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}
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}
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while (begin < end && begin >= 0 && end <=len-1){
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int tmp = arr[begin];
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arr[begin] = arr[end];
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arr[end] = tmp;
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begin ++;end--;
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}
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flag = true;
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for(int i=0;i<len-1;i++){
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if(arr[i] > arr[i+1]){
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flag = false;
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}
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}
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if(flag){
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System.out.println("yes");
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}else {
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System.out.println("no");
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}
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}
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}
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