Ａ1085. Perfect Sequence (25)

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</pre><pre name="code" class="cpp">#include<cstdio><span style="white-space:pre"></span>//两点法，为什么必须去掉下面的判断语句，当j = n-1时#include<algorithm>using namespace std;int main(){long long n,p;scanf("%lld %lld",&n,&p);long long a[n];for(int i = 0;i < n;i++)scanf("%lld",&a[i]);sort(a,a+n);int i = 0,j = 0,maxN = 1;while(i<n&& j < n){while(a[i]*p>=a[j]&&j<n) j++;//if(a[i]*p<a[j]){maxN = max(maxN,j-i);i++;//}}printf("%d\n",maxN);return 0;}

//二分法

#include<cstdio>#include<algorithm>//二分法using namespace std;int binarySearch(long long a[],int s,long long n,long long x){if(a[n-1]<=x) return n;                 <span style="white-space:pre"></span>//这个没有考虑到int l = s+1,r = n-1;while(l<r){int mid = (l+r)/2;if(a[mid]>x)r = mid;elsel = mid+1;}return l;}int main(){long long n,p;scanf("%lld %lld",&n,&p);long long a[n];for(int i = 0;i < n;i++)scanf("%lld",&a[i]);sort(a,a+n);int maxN = 1;//记录最大值for(int i = 0;i < n;i++){maxN = max(maxN,binarySearch(a,i,n,a[i]*p)-i);/*int l = i+1,r = n-1;while(l<r){int mid = (l+r)/2;if(a[i]*p>=a[mid]){//符合要求，可向右走if(mid-i>max)max = mid-i;l = mid+1;}else {//偏大,向左r = mid;}}*/}printf("%d\n",maxN);return 0;}

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