Submission #493248

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Source Code Expand

#include <iostream>
#include <vector>
#include <string>
#include <cstring>
#include <algorithm>
#include <sstream>
#include <map>
#include <set>

#define REP(i,k,n) for(int i=k;i<n;i++)
#define rep(i,n) for(int i=0;i<n;i++)
#define INF 1<<30
#define pb push_back
#define mp make_pair

using namespace std;
typedef long long ll;
typedef pair<int,int> P;

int main() {
    int n,x;
    cin >> n >> x;

    int t;
    cin >> t;

    vector<int> v(n-1),p(n);
    rep(i,n-1) cin >> v[i];
    rep(i,n) cin >> p[i];

    if(n == x) {
        cout << n << endl;
        return 0;
    }

    sort(v.begin(),v.end(),greater<int>());

    int l = 0, r = n;
    while(r - l > 1) {
        int mid = (l+r) / 2;
        int next = t + p[mid];

        vector<int> prev;
        rep(i,x) {
            prev.push_back(v[i]);
        }

        vector<int> rev;
        rep(i,n) {
            if(i == mid) continue;
            rev.push_back(p[i]);

            if(rev.size() == x) break;
        }

        reverse(rev.begin(),rev.end());

        vector<int> cost(x);
        rep(i,x) {
            cost[i] = prev[i] + rev[i];
        }

        int cnt =0;
        rep(i,x) {
            if(next < cost[i]) {
                cnt++;
            }
        }

        if(cnt >= x) {
            r = mid;
        } else {
            l = mid;
        }
    }
    
    if(l == 0) {
        int cnt = 0;
        int next = t + p[0];
        vector<int> prep(x);
        rep(i,x) {
            prep[i] = p[i+1];
        }
        reverse(prep.begin(),prep.end());
        rep(i,x) {
            if(next < v[i] + prep[i]) {
                cnt++;
            }
        }

        if(cnt >= x) {
            cout << -1 << endl;
        } else {
            cout << l+1 << endl;
        }
    } else {
        cout << l+1 << endl;
    }

    return 0;
}

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