二分

#include <cstdio>

#include <cstdlib>

#include <cmath>

#include <map>

#include <set>

#include <queue>

#include <stack>

#include <vector>

#include <sstream>

#include <string>

#include <cstring>

#include <algorithm>

#include <iostream>

#define maxn 100010

#define INF 0x7fffffff

#define inf 10000000

#define MOD 1000000007

#define ull unsigned long long

#define ll long long

using namespace std;

struct node

{

    int x, y;

};

node houge[maxn];

int n, v, w, s[maxn*10], m;

bool ok(int mid)

{

    double st = houge[0].x, en = houge[0].x+w;

    for(int i = 1; i < n; ++ i)

    {

        double len = (double)(houge[i].y-houge[i-1].y)/s[mid]*v;

        st -= len;

        en += len;

        st = max(st, (double)houge[i].x);

        en = min(en, (double)houge[i].x+w);

        if(st > en+1e-6) return false;

    }

    return true;

}

int solve()

{

    int ans = -1;

    int rig = 0, le = m;

    while(rig < le)

    {

        int mid = rig + (le-rig)/2;

        if(ok(mid))

        {

            rig = mid+1;

            ans = mid;

        }

        else le = mid;

    }

    return ans;

}

int main()

{

    int t;

    scanf("%d", &t);

    while(t --)

    {

        scanf("%d%d%d", &w, &v, &n);

        for(int i = 0; i < n; ++ i) scanf("%d%d", &houge[i].x, &houge[i].y);;

        scanf("%d", &m);

        for(int i = 0; i < m; ++ i) scanf("%d", &s[i]);

        sort(s, s+m);

        int ans = solve();

        if(ans != -1) printf("%d\n", s[ans]);

        else puts("IMPOSSIBLE");

    }

    return 0;

}