1 --无序查找
2 public static int Search(int[] a,int key){
3 for(int i=0;i<a.length;i++){
4 if(key==a[i]){
5 return i;
6 }
7 }
8 return -1;
9 }
1 --折半查找
2 public static int BinarySearch(int[] a,int key){
3 int min,max,mid;
4 min=0;
5 max=a.length-1;
6 mid =(min+max)/2;
7 while(key!=a[mid]){
8 if(key>a[mid]){
9 min=mid+1;
10 }else{
11 max=mid-1;
12 }
13 if(max<min)
14 return -1;
15
16 mid=(min+max)/2;
17 }
18 return mid;
19 }
1 --折半查找优化
2 public static int BinarySearch_2(int[] a,int key){
3 int min,max,mid;
4 min=0;
5 max=a.length-1;
6 while(max>=min){
7 mid =(min+max)>>1;
8 if(key>a[mid]){
9 min=mid+1;
10 }else if(key<a[mid]){
11 max=mid-1;
12 }else{
13 return mid;
14 }
15 }
16 return -1;
17 }
