编程之美，3.11程序改错， 二分扩展

#include <iostream>using namespace std;int find1(int *a, int start, int end, int b){//给定一个有序序列a，求任意一个i使得a[i]等于b，不存在返回-1.int mid;while(start<=end){mid = start + (end-start)/2;if(a[mid]<b){start = mid+1;}else if(a[mid] > b){end = mid-1;}else{return mid;}}return -1;}int find2(int *a, int start, int end, int b){// 给定一个有序序列a，求任意最小的i使得a[i]等于b，不存在返回-1.int mid ;while((start+1) < end){mid = start+(end-start)/2;if(a[mid] >= b)end = mid;elsestart = mid;}if(a[end] == b) return end;    else if(a[start]==b) return start;else return -1;}int find3(int *a, int start, int end, int b){// 给定一个有序序列a，求任意最大的i使得a[i]等于b，不存在返回-1.int mid ;while((start+1) < end){mid = start+(end-start)/2;if(a[mid] > b)end = mid;elsestart = mid;}if(a[end] == b) return end;    else if(a[start]==b) return start;else return -1;}int find4(int *a, int start, int end, int b){// 给定一个有序序列a，求任意最大的i使得a[i]小于b，不存在返回-1.int mid ;while((start+1) < end){mid = start+(end-start)/2;if(a[mid] < b)start = mid;elseend = mid;}if(a[start]<b && a[end]>=b) return start;else if(a[end]<b) return end;else return -1;}int find5(int*a, int start, int end, int b){//给定一个有序数组a，求最小的i使得a[i]大于b,不存在则返回-1.int mid;while((start+1) < end){mid = start + (end-start)/2;if(a[mid] > b) end = mid;else start = mid;}    if(a[start] > b) return start;else if(a[start]<=b && a[end]>b) return end;else return -1;}int main(){int a1[]={1,2,3,4,4,5};int a2[]={1,2,2,2,2,3};int a3[]={1,2,3,4,5,6};int b = 4;cout<<find5(a2,0,5,10)<<endl;cout<<find5(a3,0,5,4)<<endl;return 0;}