不使用upper_bound函数

#include <bits/stdc++.h>
#define int long long
using namespace std;
const int INF = 0x3f3f3f3f;
const int N = 1e5 + 10;
int n , m , cnt , a [N];
signed main()
{
		cin >> n >> m;
		for (int i = 1; i <= n; i++) cin >> a [i];
		while ( m-- )
		{
			cin >> cnt;
            int l = 1 , r = n , ans = 0;
            while (l <= r)
            {
                int mid = l + r >> 1;
                if (cnt >= a [mid])//要查找的值大于当前值
                {
                    if (a [mid] == cnt)
                        ans = max (ans , mid);
                    l = mid + 1;
                } 
                else r = mid - 1;
            }
            if (!ans) cout << "-1\n";
            else cout << ans << "\n";
		}
		return 0;
}

使用upper_bound函数

#include <bits/stdc++.h>
#define int long long
using namespace std;
const int INF = 0x3f3f3f3f;
const int N = 1e5 + 10;
int n , m , cnt , a [N];
signed main()
{
		cin >> n >> m;
		for (int i = 1; i <= n; i++) cin >> a [i];
		while ( m-- )
		{
			cin >> cnt;
            if (a [(upper_bound (a + 1 , a + n + 1 , cnt) - a) - 1] != cnt) cout << "-1\n";
			else cout << (upper_bound (a + 1 , a + n + 1 , cnt) - a) - 1 << "\n" ;
		}
		return 0;
}

#include<bits/stdc++.h>
using namespace std;
long long a[10000000],n,x,nnn;
int main(){
    cin >> n >> x;
    for(int i=0; i<n; i++){
        cin >> a[i];
    }
    for(int i=0; i<x; i++){
        int l=0,r=n-1,mid=0,ans=0;
        bool f=0;
        cin >> ans;
        while(l<=r){
            mid=(l+r)/2;
            if(a[mid]==ans){
                f=1;
                l=mid+1;
                nnn=mid;
            }
            else if(a[mid]<ans){
                l=mid+1;
            }
            else r=mid-1;
        }
        if(f==0){
            cout << -1 << "\n";
        }
        else cout << nnn+1 << "\n";
    }
    return 0;
}

虽然只有一种味，但真的很 鲜~

向日葵味

#include<bits/stdc++.h>
using namespace std;
int n, m;  
int a[10000005];  
int main(){
    cin >> n >> m;  
    for(int i=1; i<=n; i++){
        cin >> a[i];
    }

    for(int i=1; i<=m; i++){  
        int ans;  
        cin >> ans;
        int l = 1, r = n, res = -1;  
        while (l <= r) {
            int mid = (l + r) / 2;
            if (a[mid] == ans) {
                res = mid;  
                /*r = mid - 1;*/l = mid + 1;  
            } else if (a[mid] < ans) {
                l = mid + 1;
            } else {
                r = mid - 1;
            }
        }
        cout << res << "\n";  
    }
    return 0;
}

#include<bits/stdc++.h>
using namespace std;
int main(){
	int n,m,a[100001],b[100001],c[100005];
	cin>>n>>m;
	for(int i=1;i<=n;i++){
		cin>>a[i];
	}
	for(int i=1;i<=m;i++){
		cin>>b[i];
		int l=1,r=n,ans=0;	
	while(l<=r){
		int mid=(l+r)/2;
		if(a[mid]==b[i]){
			ans=mid;
			l=mid+1;
		}
		else if(a[mid]>b[i]){
			r=mid-1;
		}
		else if(a[mid]<b[i]){
			l=mid+1;
		}
	}
		if(ans==0){
			c[i]=-1;
		}
		else{
			c[i]=ans;
		}
	}
	for(int i=1;i<=m;i++){
		cout<<c[i]<<endl;
	}
	

	
	
	return 0;
}
//废物小鸟

#include<bits/stdc++.h>
using namespace std;
int main(){
	int n,m,a[100001],b[100001],c[100005];
	cin>>n>>m;
	for(int i=1;i<=n;i++){
		cin>>a[i];
	}
	for(int i=1;i<=m;i++){
		cin>>b[i];
		int l=1,r=n,ans=0;	
	while(l<=r){
		int mid=(l+r)/2;
		if(a[mid]==b[i]){
			ans=mid;
			l=mid+1;
		}
		else if(a[mid]>b[i]){
			r=mid-1;
		}
		else if(a[mid]<b[i]){
			l=mid+1;
		}
	}
		if(ans==0){
			c[i]=-1;
		}
		else{
			c[i]=ans;
		}
	}
	for(int i=1;i<=m;i++){
		cout<<c[i]<<endl;
	}
	

	
	
	return 0;
}
小鸟