800.数组元素目标和

思路

info

双指针什么时候从一头一尾开始遍历，什么时候同时从起点开始遍历？

代码

#include <bits/stdc++.h>

using namespace std;

const int N = 1e5 + 10;

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

int main() {
    
    cin >> n >> m >> x;
    
    for (int i = 0; i < n; i ++) cin >> a[i];
    for (int i = 0; i < m; i++) cin >> 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;
}