模版写法
#include <bits/stdc++.h>
using namespace std;
const int N = 1e5+10;
int q[N];
int main()
{
int n,m;
scanf("%d%d",&n,&m);
for(int i = 0; i < n; i ++) scanf("%d",&q[i]);
while(m--)
{
int x;
scanf("%d\n",&x);
int l = 0, r = n-1;
while(l < r)
{
int mid = l + r >> 1;
if(q[mid] >= x) r = mid; //注意check函数 范围大小 边界问题
else l = mid + 1;
}
if(q[l] != x) cout << "-1 -1" << endl;
else
{
cout << l << " ";
int l = 0, r = n-1;
while(l < r)
{
int mid = l + r + 1 >> 1;
if(q[mid] <= x) l = mid ;
else r = mid - 1;
}
cout << l << endl;
}
}
return 0;
}
写成两个函数
#include <bits/stdc++.h>
using namespace std;
const int N=1e5+10;
int n,q,a[N];
void Up(int x)
{
int l=0,r=n-1;
while (l<r)
{
int mid=l+r>>1;
if (a[mid]>=x)
r=mid;
else
l=mid+1;
}
if (a[l]!=x)
l=-1;
cout<<l<<' ';
return;
}
void Down(int x)
{
int l=0,r=n-1;
while (l<r)
{
int mid =l+r+1>>1;
if (a[mid]<=x)
l=mid;
else
r=mid-1;
}
if (a[l]!=x)
l=-1;
cout<<l<<endl;
return;
}
int main()
{
ios::sync_with_stdio(false);
cin>>n>>q;
for (int i=0; i<n; i++)
cin>>a[i];
while (q--)
{
int x;
cin>>x;
Up(x);
Down(x);
}
return 0;
}
作者:秦淮岸灯火阑珊
链接:https://www.acwing.com/solution/content/2104/
来源:AcWing
著作权归作者所有。商业转载请联系作者获得授权,非商业转载请注明出处。
#include <bits/stdc++.h>
using namespace std;
const int N = 1e5+10;
int q[N];
int n,m;
void up(int x)
{
int l = 0, r = n-1;
while(l < r)
{
int mid = l + r >> 1;
if(q[mid] >= x) r = mid;
else l =mid + 1;
}
if(q[l] != x) l = -1;
cout << l << " ";
}
void down(int x)
{
int l = 0, r = n-1;
while(l < r)
{
int mid = l + r + 1 >> 1;
if(q[mid] <= x) l = mid;
else r =mid - 1;
}
if(q[l] != x) l = -1;
cout << l << endl;
}
int main()
{
scanf("%d%d",&n,&m);
for(int i = 0; i < n; i ++) scanf("%d",&q[i]);
while(m--)
{
int x;
scanf("%d\n",&x);
up(x);
down(x);
}
return 0;
}