Algorithms—275.H-Index II

思路：二分法。

public class Solution {
public int hIndex(int[] citations) {
if (citations.length==0) {
return 0;
}
Arrays.sort(citations);
int s=0;
int e=citations.length-1;
int m=(s+e)/2;
int l=citations.length;
while (e-s>1) {
if (l<citations[s]+s) {
return l;
}
if (l==citations[m]+m) {
return l-m;
}
if (l>citations[m]+m) {
s=m;
}else {
e=m;
}
m=(s+e)/2;
}
if (l>citations[e]+e) {
return l-e-1;
}else if(l>citations[s]+s){
return l-e;
}else{
return l-s;
}
}
}