1 #include<stdio.h> 2 int a[3000]; 3 int chazhao(int n,int t) 4 { 5     int x,y,m; 6     x=0;y=n-1; 7     if(a[x]==t)x=x; 8     else if(a[y]==t) x=y; 9     else while(x<y)10     {11         m=x+(y-x)/2;12         if(a[m]>=t)y=m;13         else x=m+1;14     }15     return x;16 }17 int main()18 {19     int n,i,t;20     scanf("%d",&n);21     for(i=0;i<n;i++)22         scanf("%d",&a[i]);//输入一个有序数列23     scanf("%d",&t);24     i=chazhao(n,t);25     if(a[i]==t) printf("%d\n",i+1);26     else printf("No\n");27     return 0;28 }