二分

因为数组是单调的，所以我们可以用二分查找来做

# include <iostream>
# include <algorithm>
using namespace std;

int n,m,x;
int a[100010],b[100010];

int mid_find(int k)
{
    int l = 0,r = m-1,mid =(l+r)/2;
    while (l < r&&b[mid]!=k)
    {
        if (b[mid] > k) r = mid-1;
        if (b[mid] < k) l = mid+1;
        mid = (l+r)/2;
    }
    if (b[mid]==k) return mid;
    return 0;
}

int main ()
{
    cin >> n >> m >> x;
    for (int i = 0 ; i < n ; i++) scanf("%d",&a[i]);
    for (int i = 0 ; i < m ; i++) scanf("%d",&b[i]);

    for (int i = 0 ; i < n ; i++)
    {
        if (mid_find(x-a[i]))
        {
        cout<<i<<' '<<mid_find(x-a[i]);
        break;
        }
        else
        continue;
    }
    return 0;
}

y总的双指针算法

#include <iostream>

using namespace std;

const int N = 1e5 + 10;

int n, m, x;
int a[N], b[N];

int main()
{
    scanf("%d%d%d", &n, &m, &x);
    for (int i = 0; i < n; i ++ ) scanf("%d", &a[i]);
    for (int i = 0; i < m; i ++ ) scanf("%d", &b[i]);

    for (int i = 0, j = m - 1; i < n; i ++ )
    {
        while (j >= 0 && a[i] + b[j] > x) j -- ;
        if (j >= 0 && a[i] + b[j] == x) cout << i << ' ' << j << endl;
    }

    return 0;
}

作者：yxc
链接：https://www.acwing.com/activity/content/code/content/40069/
来源：AcWing
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