浜屽垎鎼滅储
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鏍囩锛?/p>
瀹氫箟灞€閮ㄦ渶灏忕殑姒傚康銆俛rr闀垮害涓?鏃讹紝arr[0]鏄眬閮ㄦ渶灏忋€俛rr鐨勯暱搴︿负N(N>1)鏃讹紝濡傛灉arr[0]<arr[1]锛岄偅涔坅rr[0]鏄眬閮ㄦ渶灏忥紱濡傛灉arr[N-1]<arr[N-2]锛岄偅涔坅rr[N-1]鏄眬閮ㄦ渶灏忥紱濡傛灉0<i<N-1锛屾棦鏈塧rr[i]<arr[i-1]鍙堟湁arr[i]<arr[i+1]锛岄偅涔坅rr[i]鏄眬閮ㄦ渶灏忋€?缁欏畾鏃犲簭鏁扮粍arr锛屽凡鐭rr涓换鎰忎袱涓浉閭荤殑鏁伴兘涓嶇浉绛夛紝鍐欎竴涓嚱鏁帮紝鍙渶杩斿洖arr涓换鎰忎竴涓眬閮ㄦ渶灏忓嚭鐜扮殑浣嶇疆鍗冲彲銆?/div>
public class Solution {
public static int findPartMin(int[] data,int lo,int hi){
while(lo<=hi){
int mid = lo+(hi-lo)/2;
if(data[mid]<data[mid-1]&&data[mid]<data[mid+1])
return mid;
else if(data[mid]>data[mid-1])
hi = mid-1;
else if(data[mid]>data[mid+1])
lo = mid+1;
}
return -1;
}
public int getLessIndex(int[] arr) {
if(arr.length==1)
return 0;
else if(arr.length>1){
if(arr[0]<arr[1])
return 0;
else if(arr[arr.length-1]<arr[arr.length-2])
return arr.length-1;
else
return findPartMin(arr,1,arr.length-2);
}else
return -1;
}
}
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瀵逛簬涓€涓湁搴忔暟缁刟rr锛屽啀缁欏畾涓€涓暣鏁皀um锛岃鍦╝rr涓壘鍒皀um杩欎釜鏁板嚭鐜扮殑鏈€宸﹁竟鐨勪綅缃€?/p>
缁欏畾涓€涓暟缁?strong>arr鍙婂畠鐨勫ぇ灏?strong>n锛屽悓鏃剁粰瀹?strong>num銆傝杩斿洖鎵€姹備綅缃€傝嫢璇ュ厓绱犲湪鏁扮粍涓湭鍑虹幇锛岃杩斿洖-1銆?/p>
娴嬭瘯鏍蜂緥锛?/div>
[1,2,3,3,4],5,3
杩斿洖锛?
import java.util.*;
public class LeftMostAppearance {
public int findPos(int[] arr, int n, int num) {
// write code here
int left = 0,right = n-1;
int pos = -1;
while(left<=right){
int mid = left+(right-left)/2;
if(arr[mid]>num)
right = mid-1;
else if(arr[mid]<num)
left = mid+1;
else{
pos = mid;
right = mid-1;
}
}
return pos;
}
}
鏈変竴涓湁搴忔暟缁刟rr锛屽叾涓笉鍚湁閲嶅鍏冪礌锛岃鎵惧埌婊¤冻arr[i]==i鏉′欢鐨勬渶宸︾殑浣嶇疆銆傚鏋滄墍鏈変綅缃笂鐨勬暟閮戒笉婊¤冻鏉′欢锛岃繑鍥?1銆?/p>
缁欏畾鏈夊簭鏁扮粍arr鍙婂畠鐨勫ぇ灏?strong>n锛岃杩斿洖鎵€姹傚€笺€?/p>
娴嬭瘯鏍蜂緥锛?/div>
[-1,0,2,3],4
杩斿洖锛?
import java.util.*;
public class Find {
public int findPos(int[] arr, int n) {
// write code here
int left = 0,right = n-1;
while(left<=right){
int mid = left+(right-left)/2;
if(arr[left]==left)
return left;
if(arr[mid]>mid)
right = mid-1;
else if(arr[mid]<mid)
left = mid+1;
else
return mid;
}
return -1;
}
}
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